Cyclopropyl-fused pyrrolidine-based inhibitors of dipeptidyl peptidase IV and method

ABSTRACT

Dipeptidyl peptidase IV (DP 4) inhibiting compounds are provided having the formula 
                         
where
         x is 0 or 1 and y is 0 or 1 (provided that   x=1 when y=0 and x=0 when y=1);   n is 0 or 1; X is H or CN;   and wherein R 1 , R 2 , R 3  and R 4  are as described herein.       

     A method is also provided for treating diabetes and related diseases, especially Type II diabetes, and other diseases as set out herein, employing such DP 4 inhibitor *or a combination of such DP 4 inhibitor and one or more of another antidiabetic agent such as metformin, glyburide, troglitazone, pioglitazone, rosiglitazone and/or insulin and/or one or more of a hypolipidemic agent and/or anti-obesity agent and/or other therapeutic agent.

This application takes priority from U.S. provisional application No.60/188,555, filed Mar. 10, 2000.

FIELD OF THE INVENTION

The present invention relates to cyclopropyl-fused pyrrolidine-basedinhibitors of dipeptidyl peptidase IV (DP-4), and to a method fortreating diabetes, especially Type II diabetes, as well ashyperglycemia, Syndrome X, diabetic complications, hyperinsulinemia,obesity, atherosclerosis and related diseases, as well as variousimmunomodulatory diseases and chronic inflammatory bowel disease,employing such cyclopropyl-fused pyrrolidines alone or in combinationwith another type antidiabetic agent and/or other type therapeuticagent.

BACKGROUND OF THE INVENTION

Depeptidyl peptidase IV (DP-4) is a membrane bound non-classical serineaminodipeptidase which is located in a variety of tissues (intestine,liver, lung, kidney) as well as on circulating T-lymphocytes (where theenzyme is known as CD-26). It is responsible for the metabolic cleavageof certain endogenous peptides (GLP-1(7-36), glucagon) in vivo and hasdemonstrated proteolytic activity against a variety of other peptides(GHRH, NPY, GLP-2, VIP) in vitro.

GLP-1(7-36) is a 29 amino-acid peptide derived by post-translationalprocessing of proglucagon in the small intestine. GLP-1(7-36) hasmultiple actions in vivo including the stimulation of insulin secretion,inhibition of glucagon secretion, the promotion of satiety, and theslowing of gastric emptying. Based on its physiological profile, theactions of GLP-1(7-36) are expected to be beneficial in the preventionand treatment of type II diabetes and potentially obesity. To supportthis claim, exogenous administration of GLP-1(7-36) (continuousinfusion) in diabetic patients has demonstrated efficacy in this patientpopulation. Unfortunately GLP-1(7-36) is degraded rapidly in vivo andhas been shown to have a short half-life in vivo (t1/2≈1.5 min). Basedon a study of genetically bred DP-4 KO mice and on in vivo/in vitrostudies with selective DP-4 inhibitors, DP-4 has been shown to be theprimary degrading enzyme of GLP-1(7-36) in vivo. GLP-1(7-36) is degradedby DP-4 efficiently to GLP-1(9-36), which has been speculated to act asa physiological antagonist to GLP-1(7-36). Thus, inhibition of DP-4 invivo should potentiate endogenous levels of GLP-1(7-36) and attenuateformation of its antagonist GLP-1(9-36) and thus serve to ameliorate thediabetic condition.

DESCRIPTION OF THE INVENTION

In accordance with the present invention, cyclopropyl-fusedpyrrolidine-based compounds are provided which inhibit DP-4 and have thestructure

wherein

-   -   x is 0 or 1 and y is 0 or 1 (provided that    -   x=1 when y=0 and    -   x=0 when y=1);    -   n is 0 or 1;    -   X is H or CN (that is cyano);    -   R¹, R², R³ and R⁴are the same or different and are independently        selected from H, alkyl, alkenyl, alkynyl, cycloalkyl,        cycloalkylalkyl, bicycloalkyl, tricycloalkyl, alkylcycloalkyl,        hydroxyalkyl, hydroxyalkylcycloalkyl, hydroxycycloalkyl,        hydroxybicycloalkyl, hydroxytricycloalkyl, bicycloalkylalkyl,        alkylthioalkyl, arylalkylthioalkyl, cycloalkenyl, aryl, aralkyl,        heteroaryl, heteroarylalkyl, cycloheteroalkyl and        cycloheteroalkylalkyl, all optionally substituted through        available carbon atoms with 1, 2, 3, 4 or 5 groups selected from        hydrogen, halo, alkyl, polyhaloalkyl, alkoxy, haloalkoxy,        polyhaloalkoxy, alkoxycarbonyl, alkenyl, alkynyl, cycloalkyl,        cycloalkylalkyl, polycycloalkyl, heteroarylamino, arylamino,        cycloheteroalkyl, cycloheteroalkylalkyl, hydroxy, hydroxyalkyl,        nitro, cyano, amino, substituted amino, alkylamino,        dialkylamino, thiol, alkylthio, alkylcarbonyl, acyl,        alkoxycarbonyl, aminocarbonyl, alkynylaminocarbonyl,        alkylaminocarbonyl, alkenylaminocarbonyl, alkylcarbonyloxy,        alkylcarbonylamino, arylcarbonylamino, alkylsulfonylamino,        alkylaminocarbonylamino, alkoxycarbonylamino, alkylsulfonyl,        aminosulfonyl, alkylsulfinyl, sulfonamido or sulfonyl;    -   and R¹ and R³ may optionally be taken together to form        —(CR⁵R⁶)_(m)— where m is 2 to 6, and R⁵ and R⁶ are the same or        different and are independently selected from hydroxy, alkoxy,        cyano, H, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl,        cycloalkenyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl,        cycloheteroalkyl, halo, amino, substituted amino,        cycloheteroalkylalkyl, alkylcarbonylamino, arylcarbonylamino,        alkoxycarbonylamino, aryloxycarbonylamino, alkoxycarbonyl,        aryloxycarbonyl, or alkylaminocarbonylamino, or R¹ and R⁴ may        optionally be taken together to form —(CR⁷R⁸)_(p)— where p is 2        to 6, and R⁷ and R⁸ are the same or different and are        independently selected from hydroxy, alkoxy, cyano, H, alkyl,        alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, cycloalkenyl,        aryl, arylalkyl, heteroaryl, heteroarylalkyl, cycloheteroalkyl,        halo, amino, substituted amino, cycloheteroalkylalkyl,        alkylcarbonylamino, arylcarbonylamino, alkoxycarbonylamino,        aryloxycarbonylamino, alkoxycarbonyl, aryloxycarbonyl, or        alkylaminocarbonylamino, or optionally R¹ and R³ together with

-   -    form a 5 to 7 membered ring containing a total of 2 to 4        heteroatoms selected from N, O, S, SO, or SO₂;    -   or optionally R¹ and R³ together with

-   -    form a 4 to 8 membered cycloheteroalkyl ring wherein the        cycloheteroalkyl ring has an optional aryl ring fused thereto or        an optional 3 to 7 membered cycloalkyl ring fused thereto;    -   and including pharmaceutically acceptable salts thereof, and        prodrug esters thereof, and all stereoisomers thereof.

Thus, the compounds of formula I of the invention include the followingstructures

In addition, in accordance with the present invention, a method isprovided for treating diabetes, especially Type II diabetes, as well asimpaired glucose homeostasis, impaired glucose tolerance, infertility,polycystic ovary syndrome, growth disorders, frailty, arthritis,allograft rejection in transplantation, autoimmune diseases (such asscleroderma and multiple sclerosis), various immunomodulatory diseases(such as lupus erythematosis or psoriasis), AIDS, intestinal diseases(such as necrotizing enteritis, microvillus inclusion disease or celiacdisease), inflammatory bowel syndrome, chemotherapy-induced intestinalmucosal atrophy or injury, anorexia nervosa, osteoporosis, Syndrome X,dysmetabolic syndrome, diabetic complications, hyperinsulinemia,obesity, atherosclerosis and related diseases, as well as inflammatorybowel disease (such as Crohn's disease and ulcerative colitis), whereina therapeutically effective amount of a compound of structure I (whichinhibits DP 4) is administered to a human patient in need of treatment.

The conditions, diseases, and maladies collectively referenced to as“Syndrome X” or Metabolic Syndrome are detailed in Johannsson J. Clin.Endocrinol. Metab., 82, 727-734 (1997).

In addition, in accordance with the present invention, a method isprovided for treating diabetes and related diseases as defined above andhereinafter as well as any of the other disease states mentioned above,wherein a therapeutically effective amount of a combination of acompound of structure I and one, two, three or more of other types ofantidiabetic agent(s) (which may be employed to treat diabetes andrelated diseases) and/or one, two or three or more other types oftherapeutic agent(s) is administered to a human patient in need oftreatment.

The term “diabetes and related diseases” refers to Type II diabetes,Type I diabetes, impaired glucose tolerance, obesity, hyperglycemia,Syndrome X, dysmetabolic syndrome, diabetic complications, dysmetabolicsyndrome, and hyperinsulinemia.

The conditions, diseases and maladies collectively referred to as“diabetic complications” include retinopathy, neuropathy andnephropathy, and other known complications of diabetes.

The term “other type(s) of therapeutic agents” as employed herein refersto one or more antidiabetic agents (other than DP4 inhibitors of formulaI), one or more anti-obesity agents, and/or one or more lipid-modulatingagents (including anti-atherosclerosis agents), and/or one or moreinfertility agents, one or more agents for treating polycystic ovarysyndrome, one or more agents for treating growth disorders, one or moreagents for treating frailty, one or more agents for treating arthritis,one or more agents for preventing allograft rejection intransplantation, one or more agents for treating autoimmune diseases,one or more anti-AIDS agents, one or more anti-osteoporosis agents, oneor more agents for treating immunomodulatory diseases, one or moreagents for treating chronic inflammatory bowel disease or syndromeand/or one or more agents for treating anorexia nervosa.

The term “lipid-modulating” agent as employed herein refers to agentswhich lower LDL and/or raise HDL and/or lower triglycerides and/or lowertotal cholesterol and/or other known mechanisms for therapeuticallytreating lipid disorders.

In the above methods of the invention, the compound of structure I willbe employed in a weight ratio to the antidiabetic agent or other typetherapeutic agent (depending upon its mode of operation) within therange from about 0.01:1 to about 500:1, preferably from about 0.1:1 toabout 100:1, more preferably from about 0.2:1 to about 10:1.

Preferred are compounds of formula I wherein R³ is H or alkyl, R¹ is H,alkyl, cycloalkyl, bicycloalkyl, tricycloalkyl, alkylcyclo alkyl,hydroxyalkyl, hydroxytricyclo alkyl, hydroxycycloalkyl,hydroxybicycloalkyl, or hydroxyalkylcycloalkyl, R² is H or alkyl, n is0, X is CN, x is 0 or 1 and y is 0 or 1.

Most preferred are preferred compounds of formula I as described abovewhere X is

and/or wherein the fused cyclopropyl group is identified as

Thus, preferred compounds of formula I of the invention will include themoiety:

Particularly preferred are the following compounds:

A)

wherein R¹ is alkyl, cycloalkyl, bicycloalkyl, tricycloalkyl,alkylcycloalkyl, hydroxyalkyl, hydroxycycloalkyl,hydroxyalkylcycloalkyl, hydroxybicycloalkyl or hydroxytricycloalkyl;B)

wherein R¹ is alkyl, cycloalkyl, bicycloalkyl, tricycloalkyl,hydroxybicycloalkyl, hydroxytricycloalkyl, alkylcycloalkyl,hydroxyalkyl, hydroxycycloalkyl or hydroxyalkylcycloalkyl as well as thefollowing:

DETAILED DESCRIPTION OF THE INVENTION

Compounds of the structure I may be generated by the methods as shown inthe following reaction schemes and the description thereof.

Referring to Reaction Scheme 1, compound 1, where PG₁ is a common amineprotecting group such as Boc, Cbz, or FMOC and X¹ is H or CO₂R⁹ as setout below, may be generated by methods as described herein or in theliterature (for example see Sagnard et al, Tet-Lett., 1995, 36, pp.3148-3152, Tverezovsky et al, Tetrahedron, 1997, 53, pp. 14773-14792,Hanessian et al, Bioorg. Med. Chem. Lett., 1998, 8, p. 2123-2128).Removal of the PG₁ group by conventional methods (e.g. (1) TFA or HClwhen PG₁ is Boc, or (2) H₂/Pd/C, TMSI when PG₁ is Cbz, or (3) Et₂NH whenPG₁ is (FMOC) affords the free amine 2 Amine 2 may be coupled to variousprotected amino acids such as 3 (where PG₂ can be any of the PG₁protecting groups) using standard peptide coupling conditions (e.g.EDAC/HOAT, i-BuCOCOCl/TEA, PyBop/NMM) to afford the correspondingdipeptide 4. Removal of the amine protecting group PG₂ provides compoundIa of the invention where X=H.

In the case where X¹═CO₂R⁹ (where R⁹ is alkyl or aralkyl groups such asmethyl, ethyl, t-butyl, or benzyl), the ester may be hydrolyzed under avariety of conditions, for example with aqueous NaOH in a suitablesolvent such as methanol, THF, or dioxane, to provide the acid 5.Conversion of the acid group to the primary carboxamide, affording 6,may be effected by activation of the acid group (e.g. employingi-BuOCOCl/TEA or EDAC) followed by treatment with NH₃ or an ammoniaequivalent in a solvent such as dioxane, ether, or methanol. The amidefunctionality may be converted to the nitrile group by a variety ofstandard conditions (e.g. POCl₃/pyridine/imidazole or cyanuricchloride/DMF or trifluoroacetic anhydride, THF, pyridine) to give 7.Finally, removal of the PG₂ protecting group similar to above providescompound of the invention Ib.

In a different sequence (Scheme 2), compound 1 where X¹ is CO₂R⁹ may besaponified to the acid and subsequently amidated as described above togive amide 8. Removal of the PG₁ group followed by peptide coupling to 3affords compound 6, an intermediate in the synthesis of Ib.

Alternately, the carboxamide group in 8 may be converted to the nitrileas described above to give compound 9. Deprotection of PG₁ affords 10which may be subject to standard peptide coupling conditions to afford7, an intermediate in the synthesis of Ib. Compound 10 may also begenerated by oxidation of the amine 2 (e.g. NCS) followed by hydrolysisand subsequent cyanide treatment. Compound 10 may be obtained as amixture of stereoisomers or a single isomer/diastereomer which may beepimerized (employing conventional procedures) to afford a mixture ofstereoisomers.

In a like manner, β-amino acids such as

may be coupled with 2, the free amine of 8, or 10 to give thecorresponding amides which may be converted to the β-amino acidderivatives of compound Ia or Ib following the same chemistry.

Unless otherwise indicated, the term “lower alkyl”, “alkyl” or “alk” asemployed herein alone or as part of another group includes both straightand branched chain hydrocarbons, containing 1 to 20 carbons, preferably1 to 10 carbons, more preferably 1 to 8 carbons, in the normal chain,such as methyl, ethyl, propyl, isopropyl, butyl, t-butyl, isobutyl,pentyl, hexyl, isohexyl, heptyl, 4,4-dimethylpentyl, octyl,2,2,4-trimethyl-pentyl, nonyl, decyl, undecyl, dodecyl, the variousbranched chain isomers thereof, and the like as well as such groupsincluding 1 to 4 substituents such as halo, for example F, Br, Cl or Ior CF₃, alkyl, alkoxy, aryl, aryloxy, aryl(aryl) or diaryl, arylalkyl,arylalkyloxy, alkenyl, cycloalkyl, cycloalkylalkyl, cycloalkylalkyloxy,amino, hydroxy, hydroxyalkyl, acyl, heteroaryl, heteroaryloxy,heteroarylalkyl, heteroarylalkoxy, aryloxyalkyl, alkylthio,arylalkylthio, aryloxyaryl, alkylamido, alkanoylamino,arylcarbonylamino, nitro, cyano, thiol, haloalkyl, trihaloalkyl and/oralkylthio.

Unless otherwise indicated, the term “cycloalkyl” as employed hereinalone or as part of another group includes saturated or partiallyunsaturated (containing 1 or 2 double bonds) cyclic hydrocarbon groupscontaining 1 to 3 rings, including monocyclic alkyl, bicyclic alkyl (orbicycloalkyl) and tricyclic alkyl (tricycloalkyl), containing a total of3 to 20 carbons forming the ring, preferably 3 to 10 carbons, formingthe ring and which may be fused to 1 or 2 aromatic rings as describedfor aryl, which includes cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl, cyclodecyl and cyclododecyl,cyclohexenyl, adamantyl,

any of which groups may be optionally subsituted with 1 to 4substituents such as halogen, alkyl, alkoxy, hydroxy, aryl, aryloxy,arylalkyl, cycloalkyl, hydroxyalkyl, alkylamido, alkanoylamino, oxo,acyl, arylcarbonylamino, amino, nitro, cyano, thiol and/or alkylthioand/or any of the substituents for alkyl.

The term “cycloalkenyl” as employed herein alone or as part of anothergroup refers to cyclic hydrocarbons containing 3 to 12 carbons,preferably 5 to 10 carbons and 1 or 2 double bonds. Exemplarycycloalkenyl groups include cyclopentenyl, cyclohexenyl, cycloheptenyl,cyclooctenyl, cyclohexadienyl, and cycloheptadienyl, which may beoptionally substituted as defined for cycloalkyl.

The term “cycloalkylene” as employed herein refers to a “cycloalkyl”group which includes free bonds and thus is a linking group such as

and the like, and may optionally be substituted as defined above for“cycloalkyl”.

The term “alkanoyl” as used herein alone or as part of another grouprefers to alkyl linked to a carbonyl group.

Unless otherwise indicated, the term “lower alkenyl” or “alkenyl” asused herein by itself or as part of another group refers to straight orbranched chain radicals of 2 to 20 carbons, preferably 2 to 12 carbons,and more preferably 1 to 8 carbons in the normal chain, which includeone to six double bonds in the normal chain, such as vinyl, 2-propenyl,3-butenyl, 2-butenyl, 4-pentenyl, 3-pentenyl, 2-hexenyl, 3-hexenyl,2-heptenyl, 3-heptenyl, 4-heptenyl, 3-octenyl, 3-nonenyl, 4-decenyl,3-undecenyl, 4-dodecenyl, 4,8,12-tetradecatrienyl, and the like, andwhich may be optionally substituted with 1 to 4 substituents, namely,halogen, haloalkyl, alkyl, alkoxy, alkenyl, alkynyl, aryl, arylalkyl,cycloalkyl, amino, hydroxy, heteroaryl, cycloheteroalkyl, alkanoylamino,alkylamido, arylcarbonyl-amino, nitro, cyano, thiol, alkylthio and/orany of the alkyl substituents set out herein.

Unless otherwise indicated, the term “lower alkynyl” or “alkynyl” asused herein by itself or as part of another group refers to straight orbranched chain radicals of 2 to 20 carbons, preferably 2 to 12 carbonsand more preferably 2 to 8 carbons in the normal chain, which includeone triple bond in the normal chain, such as 2-propynyl, 3-butynyl,2-butynyl, 4-pentynyl, 3-pentynyl, 2-hexynyl, 3-hexynyl, 2-heptynyl,3-heptynyl, 4-heptynyl, 3-octenyl, 3-nonenyl, 4-decenyl,3-undecenyl,4-dodecenyl and the like, and which may be optionally substituted with 1to 4 substituents, namely, halogen, haloalkyl, alkyl, alkoxy, alkenyl,alkynyl, aryl, arylalkyl, cycloalkyl, amino, heteroaryl,cycloheteroalkyl, hydroxy, alkanoylamino, alkylamido, arylcarbonylamino,nitro, cyano, thiol, and/or alkylthio, and/or any of the alkylsubstituents set out herein.

The terms “arylalkenyl” and “arylalkynyl” as used alone or as part ofanother group refer to alkenyl and alkynyl groups as described abovehaving an aryl substituent.

Where alkyl groups as defined above have single bonds for attachment toother groups at two different carbon atoms, they are termed “alkylene”groups and may optionally be substituted as defined above for “alkyl”.

Where alkenyl groups as defined above and alkynyl groups as definedabove, respectively, have single bonds for attachment at two differentcarbon atoms, they are termed “alkenylene groups” and “alkynylenegroups”, respectively, and may optionally be substituted as definedabove for “alkenyl” and “alkynyl”.

The term “halogen” or “halo” as used herein alone or as part of anothergroup refers to chlorine, bromine, fluorine, and iodine as well as CF₃,with chlorine or fluorine being preferred.

The term “metal ion” refers to alkali metal ions such as sodium,potassium or lithium and alkaline earth metal ions such as magnesium andcalcium, as well as zinc and aluminum.

Unless otherwise indicated, the term “aryl” as employed herein alone oras part of another group refers to monocyclic and bicyclic aromaticgroups containing 6 to 10 carbons in the ring portion (such as phenyl ornaphthyl including 1-naphthyl and 2-naphthyl) and may optionally includeone to three additional rings fused to a carbocyclic ring or aheterocyclic ring (such as aryl, cycloalkyl, heteroaryl orcycloheteroalkyl rings for example

and may be optionally substituted through available carbon atoms with 1,2, or 3 groups selected from hydrogen, halo, haloalkyl, alkyl,haloalkyl, alkoxy, haloalkoxy, alkenyl, trifluoromethyl,trifluoromethoxy, alkynyl, cycloalkylalkyl, cycloheteroalkyl,cycloheteroalkylalkyl, aryl, heteroaryl, arylalkyl, aryloxy,aryloxyalkyl, arylalkoxy, arylthio, arylazo, heteroarylalkyl,heteroarylalkenyl, heteroarylheteroaryl, heteroaryloxy, hydroxy, nitro,cyano, amino, substituted amino wherein the amino includes 1 or 2substituents (which are alkyl, aryl or any of the other aryl compoundsmentioned in the definitions), thiol, alkylthio, arylthio,heteroarylthio, arylthioalkyl, alkoxyarylthio, alkylcarbonyl,arylcarbonyl, alkylaminocarbonyl, arylaminocarbonyl, alkoxycarbonyl,aminocarbonyl, alkylcarbonyloxy, arylcarbonyloxy, alkylcarbonylamino,arylcarbonylamino, arylsulfinyl, arylsulfinylalkyl, arylsulfonylamino orarylsulfon-aminocarbonyl and/or any of the alkyl substituents set outherein.

Unless otherwise indicated, the term “lower alkoxy”, “alkoxy”, “aryloxy”or “aralkoxy” as employed herein alone or as part of another groupincludes any of the above alkyl, aralkyl or aryl groups linked to anoxygen atom.

Unless otherwise indicated, the term “substituted amino” as employedherein alone or as part of another group refers to amino substitutedwith one or two substituents, which may be the same or different, suchas alkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl,cycloheteroalkyl, cycloheteroalkylalkyl, cycloalkyl, cycloalkylalkylhaloalkyl, hydroxyalkyl, alkoxyalkyl or thioalkyl. These substituentsmay be further substituted with any of the R¹ groups or substituents forR¹ as set out above. In addition, the amino substituents may be takentogether with the nitrogen atom to which they are attached to form1-pyrrolidinyl, 1-piperidinyl, 1-azepinyl, 4-morpholinyl,4-thiamorpholinyl, 1-piperazinyl, 4-alkyl-1-piperazinyl,4-arylalkyl-1-piperazinyl, 4-diarylalkyl-1-piperazinyl, 1-pyrrolidinyl,1-piperidinyl, or 1-azepinyl, optionally substituted with alkyl, alkoxy,alkylthio, halo, trifluoromethyl or hydroxy.

Unless otherwise indicated, the term “lower alkylthio”, “alkylthio”,“arylthio” or “aralkylthio” as employed herein alone or as part ofanother group includes any of the above alkyl, aralkyl or aryl groupslinked to a sulfur atom.

Unless otherwise indicated, the term “lower alkylamino”, “alkylamino”,“arylamino”, or “arylalkylamino” as employed herein alone or as part ofanother group includes any of the above alkyl, aryl or arylalkyl groupslinked to a nitrogen atom.

Unless otherwise indicated, the term “acyl” as employed herein by itselfor part of another group, as defined herein, refers to an organicradical linked to a carbonyl

group; examples of acyl groups include any of the R¹ groups attached toa carbonyl, such as alkanoyl, alkenoyl, aroyl, aralkanoyl, heteroaroyl,cycloalkanoyl, cycloheteroalkanoyl and the like.

Unless otherwise indicated, the term “cycloheteroalkyl” as used hereinalone or as part of another group refers to a 5-, 6- or 7-memberedsaturated or partially unsaturated ring which includes 1 to 2 heteroatoms such as nitrogen, oxygen and/or sulfur, linked through a carbonatom or a heteroatom, where possible, optionally via the linker(CH₂)_(r) (where r is 1, 2 or 3), such as:

and the like. The above groups may include 1 to 4 substituents such asalkyl, halo, oxo and/or any of the alkyl substituents set out herein. Inaddition, any of the cycloheteroalkyl rings can be fused to acycloalkyl, aryl, heteroaryl or cycloheteroalkyl ring.

Unless otherwise indicated, the term “heteroaryl” as used herein aloneor as part of another group refers to a 5- or 6-membered aromatic ringwhich includes 1, 2, 3 or 4 hetero atoms such as nitrogen, oxygen orsulfur, and such rings fused to an aryl, cycloalkyl, heteroaryl orcycloheteroalkyl ring (e.g. benzothiophenyl, indolyl), and includespossible N-oxides. The heteroaryl group may optionally include 1 to 4substituents such as any of the substituents set out above for alkyl.Examples of heteroaryl groups include the following:

and the like.

The term “cycloheteroalkylalkyl” as used herein alone or as part ofanother group refers to cycloheteroalkyl groups as defined above linkedthrough a C atom or heteroatom to a (CH₂)_(r) chain.

The term “heteroarylalkyl” or “heteroarylalkenyl” as used herein aloneor as part of another group refers to a heteroaryl group as definedabove linked through a C atom or heteroatom to a —(CH₂)_(r)— chain,alkylene or alkenylene as defined above.

The term “polyhaloalkyl” as used herein refers to an “alkyl” group asdefined above which includes from 2 to 9, preferably from 2 to 5, halosubstituents, such as F or Cl, preferably F, such as CF₃CH₂, CF₃ orCF₃CF₂CH₂.

The term “polyhaloalkoxy” as used herein refers to an “alkoxy” or“alkyloxy” group as defined above which includes from 2 to 9, preferablyfrom 2 to 5, halo substituents, such as F or Cl, preferably F, such asCF₃CH₂O, CF₃O or CF₃CF₂CH₂O.

All stereoisomers of the compounds of the instant invention arecontemplated, either in admixture or in pure or substantially pure form.The compounds of the present invention can have asymmetric centers atany of the carbon atoms including any one or the R substituents.Consequently, compounds of formula I can exist in enantiomeric ordiastereomeric forms or in mixtures thereof. The processes forpreparation can utilize racemates, enantiomers or diastereomers asstarting materials. When diastereomeric or enantiomeric products areprepared, they can be separated by conventional methods for example,chromatographic or fractional crystallization.

Where desired, the compounds of structure I may be used in combinationwith one or more other types of antidiabetic agents (employed to treatdiabetes and related diseases) and/or one or more other types oftherapeutic agents which may be administered orally in the same dosageform, in a separate oral dosage form or by injection.

The other type of antidiabetic agent which may be optionally employed incombination with the DP4 inhibitor of formula I may be 1,2,3 or moreantidiabetic agents or antihyperglycemic agents including insulinsecretagogues or insulin sensitizers, or other antidiabetic agentspreferably having a mechanism of action different from DP4 inhibitionand may include biguanides, sulfonyl ureas, glucosidase inhibitors, PPARγ agonists, such as thiazolidinediones, SGLT2 inhibitors, PPAR α/γ dualagonists, aP2 inhibitors, glycogen phosphorylase inhibitors, advancedglycosylation end (AGE) products inhibitors, and/or meglitinides, aswell as insulin, and/or glucagon-like peptide-1 (GLP-1) or mimeticsthereof.

It is believed that the use of the compounds of structure I incombination with 1, 2, 3 or more other antidiabetic agents producesantihyperglycemic results greater than that possible from each of thesemedicaments alone and greater than the combined additiveantihyperglycemic effects produced by these medicaments.

The other antidiabetic agent may be an oral antihyperglycemic agentpreferably a biguanide such as metformin or phenformin or salts thereof,preferably metformin HCl.

Where the other antidiabetic agent is a biguanide, the compounds ofstructure I will be employed in a weight ratio to biguanide within therange from about 0.01:1 to about 100:1, preferably from about 0.1:1 toabout 5:1.

The other antidiabetic agent may also preferably be a sulfonyl urea suchas glyburide (also known as glibenclamide), glimepiride (disclosed inU.S. Pat. No. 4,379,785), glipizide, gliclazide or chlorpropamide, otherknown sulfonylureas or other antihyperglycemic agents which act on theATP-dependent channel of the β-cells, with glyburide and glipizide beingpreferred, which may be administered in the same or in separate oraldosage forms.

The compounds of structure I will be employed in a weight ratio to thesulfonyl urea in the range from about 0.01:1 to about 100:1, preferablyfrom about 0.05:1 to about 5:1.

The oral antidiabetic agent may also be a glucosidase inhibitor such asacarbose (disclosed in U.S. Pat. No. 4,904,769) or miglitol (disclosedin U.S. Pat. No. 4,639,436), which may be administered in the same or ina separate oral dosage forms.

The compounds of structure I will be employed in a weight ratio to theglucosidase inhibitor within the range from about 0.01:1 to about 100:1,preferably from about 0.2:1 to about 50:1.

The compounds of structure I may be employed in combination with a PPARγ agonist such as a thiazolidinedione oral anti-diabetic agent or otherinsulin sensitizers (which has an insulin sensitivity effect in NIDDMpatients) such as troglitazone (Warner-Lambert's Rezulin®, disclosed inU.S. Pat. No. 4,572,912), rosiglitazone (en), pioglitazone (Takeda),Mitsubishi MCC-555 (disclosed in U.S. Pat. No. 5,594,016),Glaxo-Wellcome's GL-262570, englitazone (CP-68722, Pfizer) ordarglitazone (CP-86325, Pfizer, isaglitazone (MIT/J&J), JTT-501(JPNT/P&U), L-895645 (Merck), R-119702 (Sankyo/WL), NN-2344 (Dr.Reddy/NN), or YM-440 (Yamanouchi), preferably rosiglitazone andpioglitazone.

The compounds of structure I will be employed in a weight ratio to thethiazolidinedione in an amount within the range from about 0.01:1 toabout 100:1, preferably from about 0.1:1 to about 10:1.

The sulfonyl urea and thiazolidinedione in amounts of less than about150 mg oral antidiabetic agent may be incorporated in a single tabletwith the compounds of structure I.

The compounds of structure I may also be employed in combination with aantihyperglycemic agent such as insulin or with glucagon-like peptide-1(GLP-1) such as GLP-1(1-36) amide, GLP-1(7-36) amide, GLP-1(7-36) (asdisclosed in U.S. Pat. No. 5,614,492 to Habener, disclosure of which isincorporated herein by reference), or a GLP-1 mimic such as AC2993 orExendin-4 (Amylin) and LY-315902 or LY-307167 (Lilly) and NN2211(Novo-Nordisk), which may be administered via injection, intranasal, orby transdermal or buccal devices.

Where present, metformin, the sulfonyl ureas, such as glyburide,glimepiride, glipyride, glipizide, chlorpropamide and gliclazide and theglucosidase inhibitors acarbose or miglitol or insulin (injectable,pulmonary, buccal, or oral) may be employed in formulations as describedabove and in amounts and dosing as indicated in the Physician's DeskReference (PDR).

Where present, metformin or salt thereof may be employed in amountswithin the range from about 500 to about 2000 mg per day which may beadministered in single or divided doses one to four times daily.

Where present, the thiazolidinedione anti-diabetic agent may be employedin amounts within the range from about 0.01 to about 2000 mg/day whichmay be administered in single or divided doses one to four times perday.

Where present insulin may be employed in formulations, amounts anddosing as indicated by the Physician's Desk Reference.

Where present GLP-1 peptides may be administered in oral buccalformulations, by nasal administration (for example inhalation spray) orparenterally as described in U.S. Pat. Nos. 5,346,701 (TheraTech),5,614,492 and 5,631,224 which are incorporated herein by reference.

The other antidiabetic agent may also be a PPAR α/γ dual agonist such asAR-HO39242 (Astra/Zeneca), GW-409544 (Glaxo-Wellcome), KRP297 (KyorinMerck) as well as those disclosed by Murakami et al, “A Novel InsulinSensitizer Acts As a Coligand for Peroxisome Proliferation—ActivatedReceptor Alpha (PPAR alpha) and PPAR gamma. Effect on PPAR alphaActivation on Abnormal Lipid Metabolism in Liver of Zucker Fatty Rats”,Diabetes 47, 1841-1847 (1998), and in U.S. application Ser. No.09/664,598, filed Sep. 18, 2000, (attorney file LA29NP) the disclosureof which is incorporated herein by reference, employing dosages as setout therein, which compounds designated as preferred are preferred foruse herein.

The other antidiabetic agent may be an SGLT2 inhibitor such as disclosedin U.S. application Ser. No. 09/679,027, filed Oct. 4, 2000 (attorneyfile LA49NP), which is incorporated herein by reference, employingdosages as set out herein. Preferred are the compounds designated aspreferred in the above application.

The other antidiabetic agent which may be optionally employed incombination with the DP4 inhibitor of formula I may be an aP2 inhibitorsuch as disclosed in U.S. application Ser. No. 09/391,053, filed Sep. 7,1999, and U.S. application Ser. No. 09/519,079, filed Mar. 6, 2000(attorney file LA27NP), which is incorporated herein by reference,employing dosages as set out herein. Preferred are the compoundsdesignated as preferred in the above application.

The other antidiabetic agent which may be optionally employed incombination with the DP4 inhibitor of formula I may be a glycogenphosphorylase inhibitor such as disclosed in WO 96/39384, WO 96/39385,EP 978279, WO 2000/47206, WO 99/43663, and U.S. Pat. Nos. 5,952,322 and5,998,463, WO 99/26659 and EP 1041068.

The meglitinide which may optionally be employed in combination with thecompound of formula I of the invention may be repaglinide, nateglinide(Novartis) or KAD1229 (PF/Kissei), with repaglinide being preferred.

The DP4 inhibitor of formula I will be employed in a weight ratio to themeglitinide, PPAR γ agonist, PPAR α/γ dual agonist, SGLT2 inhibitor, aP2inhibitor, or glycogen phosphorylase inhibitor within the range fromabout 0.01:1 to about 100:1, preferably from about 0.1:1 to about 10:1.

The hypolipidemic agent or lipid-modulating agent which may beoptionally employed in combination with the compounds of formula I ofthe invention may include 1,2,3 or more MTP inhibitors, HMG CoAreductase inhibitors, squalene synthetase inhibitors, fibric acidderivatives, ACAT inhibitors, lipoxygenase inhibitors, cholesterolabsorption inhibitors, ileal Na⁺/bile acid cotransporter inhibitors,upregulators of LDL receptor activity, ATP citrate lyase inhibitors,cholesteryl ester transfer protein inhibitors, bile acid sequestrants,and/or nicotinic acid and derivatives thereof.

MTP inhibitors employed herein include MTP inhibitors disclosed in U.S.Pat. No. 5,595,872, U.S. Pat. No. 5,739,135, U.S. Pat. No. 5,712,279,U.S. Pat. No. 5,760,246, U.S. Pat. No. 5,827,875, U.S. Pat. No.5,885,983 and U.S. application Ser. No. 09/175,180 filed Oct. 20, 1998,now U.S. Pat. No. 5,962,440. Preferred are each of the preferred MTPinhibitors disclosed in each of the above patents and applications.

All of the above U.S. Patents and applications are incorporated hereinby reference.

Most preferred MTP inhibitors to be employed in accordance with thepresent invention include preferred MTP inhibitors as set out in U.S.Pat. Nos. 5,739,135 and 5,712,279, and U.S. Pat. No. 5,760,246 as wellas implitapide (Bayer).

The most preferred MTP inhibitor is9-[4-[4-[[2-(2,2,2-Trifluoroethoxy)benzoyl]amino]-1-piperidinyl]butyl]-N-(2,2,2-trifluoroethyl)-9H-fluorene-9-carboxamide

The hypolipidemic agent may be an HMG CoA reductase inhibitor whichincludes, but is not limited to, mevastatin and related compounds asdisclosed in U.S. Pat. No. 3,983,140, lovastatin (mevinolin) and relatedcompounds as disclosed in U.S. Pat. No. 4,231,938, pravastatin andrelated compounds such as disclosed in U.S. Pat. No. 4,346,227,simvastatin and related compounds as disclosed in U.S. Pat. Nos.4,448,784 and 4,450,171. Other HMG CoA reductase inhibitors which may beemployed herein include, but are not limited to, fluvastatin, disclosedin U.S. Pat. No. 5,354,772, cerivastatin disclosed in U.S. Pat. Nos.5,006,530 and 5,177,080, atorvastatin disclosed in U.S. Pat. Nos.4,681,893, 5,273,995, 5,385,929 and 5,686,104, atavastatin(Nissan/Sankyo nisvastatin (NK-104)) disclosed in U.S. Pat. No.5,011,930, Shionogi-Astra/Zeneca visastatin (ZD-4522) disclosed in U.S.Pat. No. 5,260,440.

The squalene synthetase inhibitors suitable for use herein include, butare not limited to, a-phosphono-sulfonates disclosed in U.S. Pat. No.5,712,396, those disclosed by Biller et al, J. Med. Chem., 1988, Vol.11, No. 10, pp 1869-1871, including isoprenoid (phosphinyl-methyl)phosphonates as well as other known squalene synthetase inhibitors, forexample, as disclosed in U.S. Pat. Nos. 4,871,721 and 4,924,024 and inBiller, S. A., Neuenschwander, K., Ponpipom, M. M., and Poulter, C. D.,Current Pharmaceutical Design, 2, 1-40 (1996).

In addition, other squalene synthetase inhibitors suitable for useherein include the terpenoid pyrophosphates disclosed by P. Ortiz deMontellano et al, J. Med. Chem., 1977, 20, 243-249, the farnesyldiphosphate analog A and presqualene pyrophosphate (PSQ-PP) analogs asdisclosed by Corey and Volante, J. Am. Chem. Soc., 1976, 98, 1291-1293,phosphinylphosphonates reported by McClard, R. W. et al, J.A.C.S., 1987,10, 5544 and cyclopropanes reported by Capson, T. L., PhD dissertation,June, 1987, Dept. Med. Chem. U of Utah, Abstracts Table of Contents, pp16, 17, 40-43, 48-51, Summary.

Other hypolipidemic agents suitable for use herein include, but are notlimited to, fibric acid derivatives, such as fenofibrate, gemfibrozil,clofibrate, bezafibrate, ciprofibrate, clinofibrate and the like,probucol, and related compounds as disclosed in U.S. Pat. No. 3,674,836,probucol and gemfibrozil being preferred, bile acid sequestrants such ascholestyramine, colestipol and DEAE-Sephadex (Secholex®, Policexide®),as well as lipostabil (Rhone-Poulenc), Eisai E-5050 (an N-substitutedethanolamine derivative), imanixil (HOE-402), tetrahydrolipstatin (THL),istigmastanylphos-phorylcholine (SPC, Roche), aminocyclodextrin (TanabeSeiyoku), Ajinomoto AJ-814 (azulene derivative), melinamide (Sumitomo),Sandoz 58-035, American Cyanamid CL-277,082 and CL-283,546(disubstituted urea derivatives), nicotinic acid, acipimox, acifran,neomycin, p-aminosalicylic acid, aspirin, poly (diallylmethylamine)derivatives such as disclosed in U.S. Pat. No. 4,759,923, quaternaryamine poly (diallyldimethylammonium chloride) and ionenes such asdisclosed in U.S. Pat. No. 4,027,009, and other known serum cholesterollowering agents.

The other hypolipidemic agent may be an ACAT inhibitor such as disclosedin, Drugs of the Future 24, 9-15 (1999), (Avasimibe); “The ACATinhibitor, Cl-1011 is effective in the prevention and regression ofaortic fatty streak area in hamsters”, Nicolosi et al, Atherosclerosis(Shannon, Irel). (1998), 137(1), 77-85; “The pharmacological profile ofFCE 27677: a novel ACAT inhibitor with potent hypolipidemic activitymediated by selective suppression of the hepatic secretion ofApoB100-containing lipoprotein”, Ghiselli, Giancarlo, Cardiovasc. DrugRev. (1998), 16(1), 16-30; “RP 73163: a bioavailablealkylsulfinyl-diphenylimidazole ACAT inhibitor”, Smith, C., et al,Bioorg. Med. Chem. Lett. (1996), 6(1), 47-50; “ACAT inhibitors:physiologic mechanisms for hypolipidemic and anti-atheroscleroticactivities in experimental animals”, Krause et al, Editor(s): Ruffolo,Robert R., Jr.; Hollinger, Mannfred A., Inflammation: Mediators Pathways(1995), 173-98, Publisher: CRC, Boca Raton, Fla.; “ACAT inhibitors:potential anti-atherosclerotic agents”, Sliskovic et al, Curr. Med.Chem. (1994), 1(3), 204-25; “Inhibitors of acyl-CoA:cholesterol O-acyltransferase (ACAT) as hypocholesterolemic agents. 6. The firstwater-soluble ACAT inhibitor with lipid-regulating activity. Inhibitorsof acyl-CoA:cholesterol acyltransferase (ACAT). 7. Development of aseries of substituted N-phenyl-N′-[(1-phenylcyclopentyl)methyl]ureaswith enhanced hypocholesterolemic activity”, Stout et al, Chemtracts:Org. Chem. (1995), 8(6), 359-62, or TS-962 (Taisho Pharmaceutical Co.Ltd).

The hypolipidemic agent may be an upregulator of LD2 receptor activitysuch as MD-700 (Taisho Pharmaceutical Co. Ltd) and LY295427 (Eli Lilly).

The hypolipidemic agent may be a cholesterol absorption inhibitorpreferably Schering-Plough's SCH48461 as well as those disclosed inAtherosclerosis 115, 45-63 (1995) and J. Med. Chem. 41, 973 (1998).

The hypolipidemic agent may be an ileal Na⁺/bile acid cotransporterinhibitor such as disclosed in Drugs of the Future, 24, 425-430 (1999).

The lipid-modulating agent may be a cholesteryl ester transfer protein(CETP) inhibitor such as Pfizer's CP 529, 414 (WO/0038722 and EP 818448)and Pharmacia's SC-744 and SC-795.

The ATP citrate lyase inhibitor which may be employed in the combinationof the invention may include, for example, those disclosed in U.S. Pat.No. 5,447,954.

Preferred hypolipidemic agents are pravastatin, lovastatin, simvastatin,atorvastatin, fluvastatin, cerivastatin, atavastatin and ZD-4522.

The above-mentioned U.S. patents are incorporated herein by reference.The amounts and dosages employed will be as indicated in the Physician'sDesk Reference and/or in the patents set out above.

The compounds of formula I of the invention will be employed in a weightratio to the hypolipidemic agent (were present), within the range fromabout 500:1 to about 1:500, preferably from about 100:1 to about 1:100.

The dose administered must be carefully adjusted according to age,weight and condition of the patient, as well as the route ofadministration, dosage form and regimen and the desired result.

The dosages and formulations for the hypolipidemic agent will be asdisclosed in the various patents and applications discussed above.

The dosages and formulations for the other hypolipidemic agent to beemployed, where applicable, will be as set out in the latest edition ofthe Physicians' Desk Reference.

For oral administration, a satisfactory result may be obtained employingthe MTP inhibitor in an amount within the range of from about 0.01 mg/kgto about 500 mg and preferably from about 0.1 mg to about 100 mg, one tofour times daily.

A preferred oral dosage form, such as tablets or capsules, will containthe MTP inhibitor in an amount of from about 1 to about 500 mg,preferably from about 2 to about 400 mg, and more preferably from about5 to about 250 mg, one to four times daily.

For oral administration, a satisfactory result may be obtained employingan HMG CoA reductase inhibitor, for example, pravastatin, lovastatin,simvastatin, atorvastatin, fluvastatin or cerivastatin in dosagesemployed as indicated in the Physician's Desk Reference, such as in anamount within the range of from about 1 to 2000 mg, and preferably fromabout 4 to about 200 mg.

The squalene synthetase inhibitor may be employed in dosages in anamount within the range of from about 10 mg to about 2000 mg andpreferably from about 25 mg to about 200 mg.

A preferred oral dosage form, such as tablets or capsules, will containthe HMG CoA reductase inhibitor in an amount from about 0.1 to about 100mg, preferably from about 5 to about 80 mg, and more preferably fromabout 10 to about 40 mg.

A preferred oral dosage form, such as tablets or capsules will containthe squalene synthetase inhibitor in an amount of from about 10 to about500 mg, preferably from about 25 to about 200 mg.

The other hypolipidemic agent may also be a lipoxygevase inhibitorincluding a 15-lipoxygenase (15-LO) inhibitor such as benzimidazolederivatives as disclosed in WO 97/12615, 15-LO inhibitors as disclosedin WO 97/12613, isothiazolones as disclosed in WO 96/38144, and 15-LOinhibitors as disclosed by Sendobry et al “Attenuation of diet-inducedatherosclerosis in rabbits with a highly selective 15-lipoxygenaseinhibitor lacking significant antioxidant properties”, Brit. J.Pharmacology (1997) 120, 1199-1206, and Cornicelli et al,“15-Lipoxygenase and its Inhibition: A Novel Therapeutic Target forVascular Disease”, Current Pharmaceutical Design, 1999, 5, 11-20.

The compounds of formula I and the hypolipidemic agent may be employedtogether in the same oral dosage form or in separate oral dosage formstaken at the same time.

The compositions described above may be administered in the dosage formsas described above in single or divided doses of one to four timesdaily. It may be advisable to start a patient on a low dose combinationand work up gradually to a high dose combination.

The preferred hypolipidemic agent is pravastatin, simvastatin,lovastatin, atorvastatin, fluvastatin or cerivastatin.

The other type of therapeutic agent which may be optionally employedwith the DP4 inhibitor of formula I may be 1, 2, 3 or more of ananti-obesity agent including a beta 3 adrenergic agonist, a lipaseinhibitor, a serotonin (and dopamine) reuptake inhibitor, a thyroidreceptor beta drug, an anorectic agent and/or a fatty acid oxidationupregulator.

The beta 3 adrenergic agonist which may be optionally employed incombination with a compound of formula I may be AJ9677(Takeda/Dainippon), L750355 (Merck), or CP331648 (Pfizer) or other knownbeta 3 agonists as disclosed in U.S. Pat. Nos. 5,541,204, 5,770,615,5,491,134, 5,776,983 and 5,488,064, with AJ9677, L750,355 and CP331648being preferred.

The lipase inhibitor which may be optionally employed in combinationwith a compound of formula I may be orlistat or ATL-962 (Alizyme), withorlistat being preferred.

The serotonin (and dopoamine) reuptake inhibitor which may be optionallyemployed in combination with a compound of formula I may be sibutramine,topiramate (Johnson & Johnson) or axokine (Regeneron), with sibutramineand topiramate being preferred.

The thyroid receptor beta compound which may be optionally employed incombination with a compound of formula I may be a thyroid receptorligand as disclosed in WO97/21993 (U. Cal SF), WO099/00353 (KaroBio) andGB98/284425 (KaroBio), with compounds of the KaroBio applications beingpreferred.

The anorectic agent which may be optionally employed in combination witha compound of formula I may be dexamphetamine, phentermine,phenylpropanolamine or mazindol, with dexamphetamine being preferred.

The fatty acid oxidation upregulator which may be optionally employed incombination with the compound of formula I can be famoxin (Genset).

The various anti-obesity agents described above may be employed in thesame dosage form with the compound of formula I or in different dosageforms, in dosages and regimens as generally known in the art or in thePDR.

The infertility agent which may be optionally employed in combinationwith the DP4 inhibitor of the invention may be 1, 2, or more ofclomiphene citrate (Clomid®, Aventis), bromocriptine mesylate(Parlodel®, Novartis),LHRH analogs, Lupron (TAP Pharm.), danazol,Danocrine (Sanofi), progestogens or glucocorticoids, which may beemployed in amounts specified in the PDR.

The agent for polycystic ovary syndrome which may be optionally employedin combination with the DP4 inhibitor of the invention may be 1, 2, ormore of gonadotropin releasing hormone (GnRH), leuprolide (Lupron®),Clomid®, Parlodel®, oral contraceptives or insulin sensitizers such asPPAR agonists, or other conventional agents for such use which may beemployed in amounts specified in the PDR.

The agent for treating growth disorders and/or frailty which may beoptionally employed in combination with the DP4 inhibitor of theinvention may be 1, 2, or more of a growth hormone or growth hormonesecretagogue such as MK-677 (Merck), CP-424,391 (Pfizer), and compoundsdisclosed in U.S. Ser. No. 09/506,749 filed Feb. 18, 2000 (attorneydocket LA26), as well as selective androgen receptor modulators (SARMs),which is incorporated herein by reference, which may be employed inamounts specified in the PDR, where applicable.

The agent for treating arthritis which may be optionally employed incombination with the DP4 inhibitor of the invention may be 1, 2, or moreof aspirin, indomethacin, ibuprofen, diclofenac sodium, naproxen,nabumetone (Relafen®, SmithKline Beecham), tolmetin sodium (Tolectin®,Ortho-McNeil), piroxicam (Feldene®, Pfizer), ketorolac tromethamine(Toradol®, Roche), celecoxib (Celebrex®, Searle), rofecoxib (Vioxx®,Merck) and the like, which may be employed in amounts specified in thePDR.

Conventional agents for preventing allograft rejection intransplantation such as cyclosporin, Sandimmune (Novartis),azathioprine, Immuran (Faro) or methotrexate may be optionally employedin combination with the DP4 inhibitor of the invention, which may beemployed in amounts specified in the PDR.

Conventional agents for treating autoimmune diseases such as multiplesclerosis and immunomodulatory diseases such as lupus erythematosis,psoriasis, for example, azathioprine, Immuran, cyclophosphamide, NSAIDSsuch as ibuprofen, cox 2 inhibitors such as Vioxx and Celebrex,glucocorticoids and hydroxychloroquine, may be optionally employed incombination with the DP4 inhibitor of the invention, which may beemployed in amounts specified in the PDR.

The AIDS agent which may be optionally employed in combination with theDP4 inhibitor of the invention may be a non-nucleoside reversetranscriptase inhibitor, a nucleoside reverse transcriptase inhibitor, aprotease inhibitor and/or an AIDS adjunct anti-infective and may be 1,2, or more of dronabinol (Marinol®, Roxane Labs), didanosine (Videx®,Bristol-Myers Squibb), megestrol acetate (Megace®, Bristol-MyersSquibb), stavudine (Zerit®, Bristol-Myers Squibb), delavirdine mesylate(Rescriptor®, Pharmacia), lamivudine/zidovudine (Combivir™, Glaxo),lamivudine (Epivir™, Glaxo), zalcitabine (Hivid®, Roche), zidovudine(Retrovir®, Glaxo), indinavir sulfate (Crixivan®, Merck), saquinavir(Fortovase™, Roche), saquinovir mesylate (Invirase®, Roche), ritonavir(Norvir®, Abbott), nelfinavir (Viracept®, Agouron).

The above anti-AIDS agents may be employed in amounts specified in thePDR.

The agent for treating inflammatory bowel disease or syndrome which maybe optionally employed in combination with the DP4 inhibitor of theinvention may be 1, 2, or more of sulfasalazine, salicylates, mesalamine(Asacol®, P&G) or Zelmac®, (Bristol-Myers Squibb), which may be employedin amounts specified in the PDR or otherwise known in the art.

The agent for treating osteoporosis which may be optionally employed incombination with the DP4 inhibitor of the invention may be 1, 2, or moreof alendronate sodium (Fosamax®, Merck, tiludronate (Skelid®, Sanofi),etidronate disodium (Didronel®, P&G), raloxifene HCl (Evista®, Lilly),which may be employed in amounts specified in the PDR.

In carrying our the method of the invention, a pharmaceuticalcomposition will be employed containing the compounds of structure I,with or without another antidiabetic agent and/or other type therapeuticagent, in association with a pharmaceutical vehicle or diluent. Thepharmaceutical composition can be formulated employing conventionalsolid or liquid vehicles or diluents and pharmaceutical additives of atype appropriate to the mode of desired administration. The compoundscan be administered to mammalian species including humans, monkeys,dogs, etc. by an oral route, for example, in the form of tablets,capsules, granules or powders, or they can be administered by aparenteral route in the form of injectable preparations. The dose foradults is preferably between 10 and 1,000 mg per day, which can beadministered in a single dose or in the form of individual doses from1-4 times per day.

A typical capsule for oral administration contains compounds ofstructure I (250 mg), lactose (75 mg) and magnesium stearate (15 mg).The mixture is passed through a 60 mesh sieve and packed into a No. 1gelatin capsule.

A typical injectable preparation is produced by aseptically placing 250mg of compounds of structure I into a vial, aseptically freeze-dryingand sealing. For use, the contents of the vial are mixed with 2 mL ofphysiological saline, to produce an injectable preparation.

DP4 inhibitor activity of the compounds of the invention may bedetermined by use of an in vitro assay system which measures thepotentiation of inhibition of DP4. Inhibition constants (Ki values) forthe DP4 inhibitors of the invention may be determined by the methoddescribed below.

Purification of Porcine Dipeptidyl Peptidase IV

Porcine enzyme was purified as previously described (1), with severalmodifications. Kidneys from 15-20 animals were obtained, and the cortexwas dissected away and frozen at −80° C. Frozen tissue (2000 -2500 g)was homogenized in 12 L of 0.25 M sucrose in a Waring blender. Thehomogenate then was left at 37° C. for 18 hours to facilitate cleavageof DP-4 from cell membranes. After the cleavage step, the homogenate wasclarified by centrifugation at 7000×g for 20 min at 4° C., and thesupernatant was collected. Solid ammonium sulfate was added to 60%saturation, and the precipitate was collected by centrifugation at10,000×g and was discarded. Additional ammonium sulfate was added to thesupernatant to 80% saturation, and the 80% pellet was collected anddissolved in 20 mM Na₂HPO₄, pH 7.4.

After dialysis against 20 mM Na₂HPO₄, pH 7.4, the preparation wasclarified by centrifugation at 10,000×g. The clarified preparation thenwas applied to 300 mL of ConA Sepharose that had been equilibrated inthe same buffer. After washing with buffer to a constant A₂₈₀, thecolumn was eluted with 5% (w/v) methyl α-D-mannopyranoside. Activefractions were pooled, concentrated, and dialyzed against 5 mM sodiumacetate, pH 5.0. Dialyzed material then was flowed through a 100 mLPharmacia Resource S column equilibrated in the same buffer. The flowthrough material was collected and contained most of the enzymeactivity. Active material again was concentrated and dialyzed into 20 mMNa₂HPO₄, pH 7.4. Lastly, the concentrated enzyme was chromatographed ona Pharmacia S-200 gel filtration column to removed low molecular weightcontaminants. Purity of column fractions was analyzed by reducingSDS-PAGE, and the purest fractions were pooled and concentrated.Purified enzyme was stored in 20% glycerol at −80° C.

Assay of Porcine Dipeptidyl Peptidase IV

Enzyme was assayed under steady-state conditions as previously described(2) with gly-pro-p-nitroanilide as substrate, with the followingmodifications. Reactions contained, in a final volume of 100 μl, 100 mMAces, 52 mM TRIS, 52 mM ethanolamine, 500 μM gly-pro-p-nitroanilide, 0.2% DMSO, and 4.5 nM enzyme at 25° C., pH 7.4. For single assays at 10 μMtest compound, buffer, compound, and enzyme were added to wells of a 96well microtiter plate, and were incubated at room temperature for 5 min.Reactions were started by addition of substrate, The continuousproduction of p-nitroaniline was measured at 405 nM for 15 min using aMolecular Devices Tmax plate reader, with a read every 9 seconds. Thelinear rate of p-nitroaniline production was obtained over the linearportion of each progress curve. A standard curve for p-nitroanilineabsorbance was obtained at the beginning of each experiment, and enzymecatalyzed p-nitroaniline production was quantitated from the standardcurve. Compounds giving greater than 50% inhibition were selected forfurther analysis.

For analysis of positive compounds, steady-state kinetic inhibitionconstants were determined as a function of both substrate and inhibitorconcentration. Substrate saturation curves were obtained atgly-pro-p-nitroanilide concentrations from 60 μM to 3600 μM. Additionalsaturation curves also were obtained in the presence of inhibitor.Complete inhibition experiments contained 11 substrate and 7 inhibitorconcentrations, with triplicate determinations across plates. For tightbinding inhibitors with K_(i)s less than 20 nM, the enzyme concentrationwas reduced to 0.5 nM and reaction times were increased to 120 min.Pooled datasets from the three plates were fitted to the appropriateequation for either competitive, noncompetitive or uncompetitiveinhibition.

(1) Rahfeld, J. Schutkowski, M., Faust, J., Neubert., Barth, A., andHeins, J. (1991) Biol. Chem. Hoppe-Seyler, 372, 313-318.

(2) Nagatsu, T., Hino, M., Fuyamada, H., Hayakawa, T., Sakakibara, S.,Nakagawa, Y, and Takemoto, T. (1976) Anal. Biochem., 74, 466-476.

The following abbreviations are employed in the Examples and elsewhereherein:

-   -   Ph=phenyl    -   Bn=benzyl    -   i-Bu=iso-butyl    -   Me=methyl    -   Et=ethyl    -   Pr=propyl    -   Bu=butyl    -   TMS=trimethylsilyl    -   FMOC=fluorenylmethoxycarbonyl    -   Boc or BOC=tert-butoxycarbonyl    -   Cbz=carbobenzyloxy or carbobenzoxy or benzyloxycarbonyl    -   HOAc or AcOH=acetic acid    -   DMF=N,N-dimethylformamide    -   EtOAc=ethyl acetate    -   THF=tetrahydrofuran    -   TFA=trifluoroacetic acid    -   Et₂NH=diethylamine    -   NMM=N-methyl morpholine    -   n-BuLi=n-butyllithium    -   Pd/C=palladium on carbon    -   PtO₂=platinum oxide    -   TEA=triethylamine    -   EDAC=3-ethyl-3′-(dimethylamino)propyl-carbodiimide hydrochloride        (or 1-[(3-(dimethyl)amino)propyl])-3-ethylcarbodiimide        hydrochloride)    -   HOBT or HOBT.H₂O=1-hydroxybenzotriazole hydrate    -   HOAT=1-hydroxy-7-azabenzotriazole    -   PyBOP reagent=benzotriazol-1-yloxy-tripyrrolidino phosphonium        hexafluorophosphate    -   min=minute(s)    -   h or hr=hour(s)    -   L=liter    -   mL=milliliter    -   μL=microliter    -   g=gram(s)    -   mg=milligram(s)    -   mol=mole(s)    -   mmol=millimole(s)    -   meq=milliequivalent    -   rt=room temperature    -   sat or sat'd=saturated    -   aq.=aqueous    -   TLC=thin layer chromatography    -   HPLC=high performance liquid chromatography    -   LC/MS=high performance liquid chromatography/mass spectrometry    -   MS or Mass Spec=mass spectrometry    -   NMR=nuclear magnetic resonance    -   mp=melting point

The following Examples represent preferred embodiments of the invention.

EXAMPLE 1

Step 1 title compound was synthesized by following the literatureprocedure [Stephen Hanessian, Ulrich Reinhold, Michel Saulnier, andStephen Claridge; Bioorganic & Medicinal Chemistry Letters 8 (1998)2123-2128] or with the following modifications. L-pyroglutamic acidethyl ester was N-protected as the t-butylcarbamate (Boc₂₀, DMAP or NaH)and then dehydrated to the 4,5-dehydroproline ethyl ester in one pot bycarbonyl reduction (triethylborohydride, toluene, −78° C.) followed bydehydration (TFAA, lutidine). The title compound was obtained bycyclopropanation of the 4,5-dehydroproline ethyl ester (Et₂Zn, ClCH₂I,1,2-dichloroethane, −15° C.). A more detailed protocol is as follows;

Synthesis of 4,5-dehydro-L-proline ethyl ester: L-pyroglutamic acidethyl ester (200 g, 1.27 mol) was dissolved in 1.2 liters of methylenechloride and treated sequentially with di-tert-butyldicarbonate (297 g,1.36 mol) and a catalytic DMAP (1.55 g, 0.013 mol) at ambienttemperature. After 6 h, the mixture was quenched with saturated brineand the organic phase was dried (Na₂SO₄) and filtered through a shortsilica gel column to give 323 g (100%) of N-Boc- L-pyroglutamic acidethyl ester. N-Boc-L-pyroglutamic acid ethyl ester (160 g, 0.62 mol) wasdissolved in 1 liter of toluene, cooled to −78° C. and treated withlithium triethylborohydride (666 mL of a 1.0 M soln in THF) and addeddropwise over 90 minutes. After 3 h, 2,6-lutidine (423 mL, 3.73 mol) wasadded dropwise followed by DMAP (0.2 g, 0.0016 mol). To this mixture wasadded TFAA (157 g, 0.74 mol) and the reaction was allowed to come toambient temperature over 2 h. The mixture was diluted with EtOAc andwater and the organics were washed with 3 N HCl, water, aqueousbicarbonate and brine and dried (Na₂SO₄) and filtered through a silicagel plug to give 165 g of the crude 4,5-dehydroproline ethyl ester thatwas purified by flash column chromatography on silica gel with 1:5 ethylacetate:hexanes to give 120 g, 75% of the olefin.

Cyclopropanation of 4,5-dehydro-L-proline ethyl ester:4,5-Dehydro-L-proline ethyl ester (35.0 g, 0.145 mol) was added to asolution of neat Et₂Zn (35.8 g, 0.209 mol) in 1 liter of1,2-dichloroethane at −15° C. To this mixture was added a dropwiseaddition of ClCH₂I (102 g, 0.58 mol) over 1 h and the mixture stirred at−15° C. for 18 h. The reaction was quenched with saturated aqueousbicarbonate and the solvent was evaporated and the reaction was taken upin EtOAc, washed with brine and purified by silica gel chromatographyusing a stepwise gradient of from 20% EtOAc/hexanes to 50% EtOAc/hexanesto give 17.5 g (50%) of diastereomerically pure step 1 title compound.

To a stirred solution of Step 1 compound (411 mg, 1.61 mmol) in CH₂Cl₂(1.5 mL) at rt was added TFA (1.5 mL). The reaction mixture was stirredat rt for 2 h and evaporated. The residue was diluted with CH₂Cl₂ andthen evaporated and re-evaporated three times to give the title compoundas a colorless oil, 433 mg, 100% yield,

To a stirred solution of (S)-N-tert-butoxycarbonylisoleucine (372.6 mg,1.61 mmol) and benzotriazol-1-yloxytripyrrolidinophosphoniumhexafluorophosphate (1.25 g, 2.42 mmol) in CH₂Cl₂ (6 mL) under nitrogenat rt was added 4-methylmorpholine (NMM) (0.36 mL, 3.2 mmol). After 5min, a solution of Step 2 compound (433 mg, 1.61 mmol) and NMM (0.27 mL,2.4 mmol) in CH₂Cl₂ (1 mL) was added. After addition, the reactionmixture was stirred under nitrogen at room temperature overnight. Thereaction mixture was diluted with CH₂Cl₂ (40 mL) and washed with 4%KHSO₄(10 mL), aqueous NaHCO₃(10 mL) and brine (10 mL), dried (Na₂SO₄)and evaporated. Purification by flash chromatography (1:4 EtOAc/hexane)gave the title compound as a colorless oil, 530 mg, 89% yield.

To a stirred solution of Step 3 compound (530 mg, 1.44 mmol) in MeOH (4mL) and H₂O (4 mL) at rt was added LiOH—H₂O (91 mg, 2.16 mmol). Thereaction mixture was stirred at rt overnight and evaporated. Water (10mL) was added to the residue and extracted with Et₂O (2×10 mL). Theaqueous layer was acidified to ˜pH 4 by adding 4% KHSO₄ dropwise. Themilky solution was extracted with EtOAc (15 mL×3). Combined EtOAc layerswere washed with brine, dried over Na₂SO₄ and evaporated to give thetitle compound as a white solid, 440 mg, 90% yield.

To a stirred solution of Step 4 compound (300 mg, 0.88 mmol) in THF (6mL) at −15° C. under nitrogen, was added 4-methylmorpholine (0.12 mL,1.06 mmol) and then isobutyl chloroformate (0.13 mL, 0.97 mmol) over 2min. White precipitate was formed. The reaction mixture was stirred at−15° C. under nitrogen for 25 min and a solution of NH₃ in dioxane (8.8mL, 4.4 mmol) was added. The reaction mixture was stirred at −15° C. for30 min, warmed to rt and stirred at rt overnight. The reaction mixturewas quenched by 4% KHSO₄ to ˜pH 4 and extracted with EtOAc (20 mL×3).The extracts were combined, washed with brine (10 mL) dried (Na₂SO₄) andevaporated. Purification by flash column chromatography (1:1EtOAc/hexane) gave the title compound as a white foam, 268 mg, 90%yield.

To a stirred solution of Step 5 compound (248 mg, 1.38 mmol) andimidazole (94 mg, 1.38 mmol) in dry pyridine (12 mL) at −35° C. undernitrogen was added POCl₃ (0.26 mL, 2.76 mmol) dropwise. The reactionmixture was stirred between −35° C. to −20° C. for 1 h and evaporated.CH₂Cl₂ (10 mL) was added and white precipitates were formed. Afterfiltration, the filtrate was concentrated and purified by flashchromatography (2:5 EtOAc/hexane) to give the title compound as acolorless oil, 196 mg, 88% yield.

To a stirred solution of Step 6 compound (130 mg, 0.4 mmol) in CH₂Cl₂ (2mL) at rt was added TFA (2 mL). The reaction mixture was stirred at rtfor 2 h. The reaction mixture was added slowly to a pre-cooled slurry ofNaHCO₃ (3.8 g) in H₂O (3 mL). The mixture was extracted with CH₂Cl₂ (6mL×5), and the. combined CH₂Cl₂ layers were evaporated and purified bypreparative HPLC to give the title compound as a white powder, 77 mg.57% yield, mp=141-143° C. LC/MS gave the correct molecular ion[(M+H)⁺=222] for the desired compound.

EXAMPLE 2

Step 1 title compound was synthesized by following the literatureprocedure. [Stephen Hanessian, Ulrich Reinhold, Michel Saulnier, andStephen Claridge; Bioorganic & Medicinal Chemistry Letters 8 (1998)2123-2128.]

The title compound was prepared from Step 1 compound, employing the sameprocedure as that described for Example 1, Steps 2-6. LC/MS gave thecorrect molecular ion [(M+H)⁺=222] for the desired compound.

EXAMPLE 3

Step 1 title compound was prepared by following the literatureprocedure. [Willy D. Kollmeyer, U.S. Pat. No. 4,183,857.].

To a stirred solution of (S)-N-tert-butoxycarbonylisoleucine (231 mg, 1mmol) and benzotriazol-1-yloxytripyrrolidinophosphoniumhexafluorophosphate (780 mg, 1.5 mmol) in CH₂Cl₂ (6 mL) under nitrogenat rt was added 4-methylmorpholine (0.33 mL, 3 mmol). After 5 min, Step1 compound (120 mg, 1 mmol) was added in one portion. The reactionmixture was stirred under nitrogen at rt overnight and then diluted withCH₂Cl₂ (30 mL), washed with 4.1% KHSO₄ (10 mL)), aqueous NaHCO₃ (10 mL),brine (10 mL), dried (Na₂SO₄) and evaporated. Purification by flashchromatography on silica gel (2.4×20 cm column, 1:3 EtOAc/hexane) gavethe title compound as a colorless oil, 290 mg, 90% yield. LC/MS gave thecorrect molecular ion [(M+H)⁺=297] for the desired compound.

The reaction mixture of Step 2 compound (220 mg, 0.74 mmol) and 4 M HClin dioxane (1.5 mL, 6 mmol) was stirred at rt for 2 h and evaporatedunder reduced pressure. Et₂O was added to the residue and a precipitatewas formed. Et₂O was decanted and this was done three times. Theprecipitate was dried in vacuo to give the title compound as a whitepowder, 130 mg (76% yield), mp 205-206° C. LC/MS gave the correctmolecular ion [(M+H)⁺=197] for the desired compound.

EXAMPLES 4-4A

Step 1 title compound, as a 1:1 ratio of enantiomers, was prepared byfollowing the literature procedure. [Willy D. Kollmeyer, U.S. Pat. No.4,183,857.]

A slurry of (S)-N-tert-butoxycarbonyl-isoleucine (92.5 mg, 0.4 mmol),1-[(3-(dimethyl)amino)propyl]-3-ethylcarbodiimide (77 mg, 0.4 mmol) andHOAT (54.4 mg, 0.4 mmol) in ClCH₂CH₂Cl (0.3 mL) was stirred undernitrogen at rt for 1 h, then Step 1 compound (22 mg, 0.2 mmol) wasadded, followed by Et₃N (0.015 mL, 0.1 mmol). The reaction mixture wasstirred under nitrogen at rt over night and then diluted with CH₂Cl₂ (3mL), washed with H₂O (1 mL), aqueous NaHCO₃(1 mL) and brine (1 mL),dried (Na₂SO₄) and evaporated. Purification by flash chromatography onsilica gel (2.4×12 cm column, 2:7 EtOAc/hexane) gave the title compoundas a colorless oil, 33 mg, 51% yield. LC/MS gave the correct molecularion [(M+H)⁺322] for the desired compound.

To a stirred solution of Step 2 compound (30 mg, 0.4 mmol) in CH₂Cl₂(0.5 mL) at rt was added TFA (0.5 mL). The reaction mixture was stirredat rt for 2 h. The reaction mixture was added slowly to a precooledslurry of NaHCO₃ (0.8 g) in H₂O (1 mL). The mixture was extracted withCH₂Cl₂ (2 mL×5), and combined CH₂Cl₂ layers were evaporated and purifiedby preparative HPLC to give the title compounds as a 1:1 ratio ofdiastereomers, 22 mg, 73% yield. LC/MS gave the correct molecular ion[(M+H)⁺=222] for the desired compounds.

EXAMPLES 5-5A

To a solution of Example 4, Step 1 compound (150 mg, 1.39 mmol) in2-propanol (0.8 mL), was added NaCN (40 mg, 1.0 mmol). The reactionmixture was heated to reflux for 3 h. After cooling to rt, the reactionmixture was evaporated and then slurried in Et₂O (5 mL). Afterfiltration, the filtrate was evaporated to give Example 4 Step 1compounds and Example 5 Step 1 compounds (140 mg, 93%) as a 2:1 mixtureof diastereomers, each as a racemic mixture.

A slurry of (S)-N-tert-butoxycarbonyl-isoleucine (595 mg, 2.57 mmol),1-[(3-(dimethyl)amino)propyl]-3-ethylcarbodiimide (493 mg, 2.57 mmol)and 1-hydroxy-7-azabenzotriazole (350 mg, 2.57 mmol) in ClCH₂CH₂Cl (2mL) was stirred under nitrogen at rt for 1 h, then Step 1 compoundmixture (139 mg, 1.28 mmol) was added. The reaction mixture was stirredunder nitrogen at rt overnight and then diluted with CH₂Cl₂ (30 mL),washed with H₂O (10 mL) , saturated aqueous NaHCO₃ (10 mL) and brine (10mL), dried (Na₂SO₄) and evaporated. Purification by flash chromatographyon silica gel (2.4×20 cm column, 1:3 EtOAc/hexane) gave the Example 4,Step 2 compound (260 mg), and the title compounds (105 mg) as a ratio of1:1 diastereomers. LC/MS gave the correct molecular ion [(M+H)⁺=322] forthe desired compounds.

To a stirred solution of Step 2 compounds (104 mg, 0.32 mmol) in CH₂Cl₂(1 mL) at rt was added TFA (1 mL). The reaction mixture was stirred atrt for 2 h. The reaction mixture was added slowly to a precooled slurryof NaHCO₃ (2 g) in H₂O (2 mL). The mixture was extracted with CH₂Cl₂ (4mL×4), and combined CH₂Cl₂ layers were evaporated and purified bypreparative HPLC to give the title compound Example 5 (36 mg) andExample 5A (36 mg). LC/MS gave the correct molecular ion [(M+H)⁺=222]for the desired compounds.

EXAMPLE 6

General Method A: Parallel array synthesis methods for preparation ofinhibitors from commercially available amino acids. As shown in Scheme3, the ester 11, described in Example 1 Step 1, was saponified to theacid with LiOH in THF/H₂O and converted to the amide 12 by treatmentwith isobutyl chloroformate/NMM followed by ammonia in dioxane. The Bocprotecting group was removed under acidic conditions using TFA inmethylene chloride to give 13. The TFA salt was coupled toBoc-t-butylglycine using either EDAC/HOBT/DMF or EDAC/DMAP/CH₂Cl₂ togive 14. The amide was dehydrated to the nitrile 15 usingPOCl₃/imidazole in pyridine at −20° C. and finally deprotected with TFAin CH₂Cl₂ at ambient temperature to afford the target 16. SCHEME 3,GENERAL METHOD A (EXAMPLES 6-27)

To a stirred solution of Example 1 Step 1 compound (1.40 g, 5.49 mmol)in 40 mL of a 1:1 methanol:water solution at rt was added lithiumhydroxide (0.20 g, 8.30 mmol). The reaction mixture was stirred at rtfor 18 h and then heated to 50° C. for 2 h. The mixture was diluted withequal volumes of ether and water (50 mL) and then acidified with KHSO₄to pH 3. The milky solution was extracted with ether (3×20 mL). Thecombined ether layers were dried over Na₂SO₄ and evaporated. The residuewas stripped from toluene (2×10 mL) and dried under reduced pressure togive the title compound as a thick syrup, 1.20 g, 96%.

To a stirred solution of Step 1 compound (1.20 g, 5.28 mmol) in THF (20mL) at −15° C. under nitrogen was added 4-methylmorpholine (0.71 mL,6.50 mmol) and then isobutyl chloroformate (0.78 mL, 6.00 mmol) over 5min. The reaction was stirred at −15° C. for 30 min, cooled to −30° C.and treated with a solution of NH₃ in dioxane (50 mL, 25 mmol). Thereaction mixture was stirred at −30° C. for 30 min, warmed to rt andstirred overnight. The reaction mixture was quenched with citric acidsolution (pH 4) and extracted with ether (3×50 mL). The combined organicfractions were washed with brine, dried over Na₂SO₄ and concentrated.Purification by flash column chromatography on silica gel with EtOAcgave the Step 2 compound, 1.00 g, 84%.

To a stirred solution of Step 2 compound (0.90 g, 4.00 mmol) in CH₂Cl₂(3 mL) at 0° C. was added TFA (3 mL). The reaction mixture was stirredat 0° C. for 18 h. The reaction mixture was concentrated under reducedpressure to produce title compound in the form of a thick oil, 0.98 g,100%. The oil gradually solidified upon prolonged standing.

An oven-dried 15-mL test tube was charged with Step 3 compound (56 mg,0.22 mmol), N-tert-butoxycarbonyl-(L)-tert-leucine (53 mg, 0.23 mmol),dimethylaminopyridine (0.11 g, 0.88 mmol), and CH₂Cl₂ (4 mL). The tubewas sealed under nitrogen atmosphere and treated with1-[(3-(dimethypamino)propyl]-3-ethylcarbodiimide (84 mg, 0.44 mmol). Themixture was placed in a shaker and vortexed overnight. The product waspurified by solid phase extraction using a United Technology SCX column(2 g of sorbent in a 6 mL column) by loading the material on a SCX ionexchange column and successively washing with CH₂Cl₂ (5 mL), 30%methanol in CH₂Cl₂ (5 mL), 50% methanol in CH₂Cl₂ (5 mL) and methanol(10 mL). The product containing fractions were concentrated underreduced pressure to give the desired amide. Further purification byreverse phase preparative column chromatography on a YMC S5 ODS 20×250mm column gave the title compound, 50 mg (68% yield). Purificationconditions: Gradient elution from 30% methanol/water/0.1 TFA to 90%methanol/water/0.1 TFA over 15 min. 5 min hold at 90% methanol/water/0.1TFA. Flow rate: 20 mL/min Detection wavelength: 220. Retention Time: 14min.

An oven-dried 15-mL test tube was charged with Step 4 compound (50 mg,0.15 mmol), imidazole (31 mg, 0.46 mmol), and pyridine (1 mL). The tubewas sealed under nitrogen atmosphere and cooled to −30° C. Slow additionof POCl₃ (141 mg, 88 uL, 0.92 mmol) gave after mixing a thick slurry.The tube was mixed at −30° C. for 3 h and the volatiles evaporated. Theproduct was purified by solid phase extraction using a United Technologysilica extraction column (2 g of sorbent in a 6 mL column) by loadingthe material on a silica column and successively washing with CH₂Cl₂ (5mL), 5% methanol in CH₂Cl₂ (5 mL), 7% methanol in CH₂Cl₂ (5 mL) and 12%methanol in CH₂Cl₂ (10 mL). The product containing fractions were pooledand concentrated under reduced pressure to give the title compound, 46mg, 96%.

An oven-dried 15-mL test tube was charged with Step 5 compound (0.45 mg,0.14 mmol), CH₂Cl₂ (1 mL), and TFA (1 mL). The reaction mixture wasvortexed for 40 min at rt, diluted with toluene (4 mL) and concentratedunder reduced pressure to a thick oil. The product was purified byreverse phase preparative column chromatography on a YMC S5 ODS 20×250mm column to give the Example 6 compound, 14 mg, 35%. Purificationconditions: gradient elution from 10% methanol/water/0.1 TFA to 90%methanol/water/0.1 TFA over 18 min; 5 min hold at 90% methanol/water/0.1TFA. Flow rate: 20 mL/min Detection wavelength: 220. Retention Time: 10min.

Examples 7-27 were prepared from amino acids available from commercialsources according to the procedure in Example 6.

TABLE 1

Example R [M + H] 7

302 8

295 9

240 10

222 11

222 12

222 13

208 14

270 15

222 16

206 17

256 18

268 19

220 20

220 21

210 22

262 23

242 24

210 25

281 26

281 27

272

EXAMPLE 27

(2S,4S,5S)-4,5-methano-L-proline carboxylamide, TFA salt (53 mg, 0.22mmol) was coupled to N-Boc-L-Tyrosine-benzyl ether (82 mg, 0.22 mmol)using PyBop (172 mg, 0.33 mmol) and N-methylmorpholine (67 mg, 0.66mmol) in 4 mL CH₂Cl₂. The reaction stirred for 16 h, was taken up inEtOAc, washed with H₂O, 1N aqueous HCl, brine, then evaporated andpurified by silica gel flash chromatography to give the coupled product(FAB MH+480).

The Step 1 amide was dehydrated to the nitrile using the general methodC (which follows Example 29) (FAB MH+462).

The Step 2 benzyl ether was cleaved by catalytic hydrogenolysis using10% palladium on carbon and 1 atmosphere hydrogen gas in MeOH at rt for1.5 h. The reaction was filtered through celite and concentrated to anoil and taken on without further purification (FAB MH+372).

Step 3N-[N-Boc-L-Tyrosine-]-(2S,4S,5S)-2-cyano-4,5-methano-L-prolylamide wasdissolved in CH₂Cl₂ and TFA was added at rt. The reaction stirred for 1h and was evaporated and purified by preparative HPLC as described ingeneral method B (set out following Example 29) to afford the titlecompound (FAB MH+272).

EXAMPLE 28

The title compound was prepared by coupling(2S,4S,5S)-4,5-methano-L-proline carboxylamide, TFA salt described inExample 6 Step 3 compound with N-(tert-butyloxy-carbonylhydroxyvaline.After hydroxyl protection with triethylsilyl chloride and dehydration ofthe amide with POCl₃/imidazole in pyridine and deprotection (N-terminalnitrogen and valine hydroxyl) with TFA using general method C (FABMH+224), the title compound was obtained.

EXAMPLE 29

N-Boc-L-homoserine (1.20 g, 5.47 mmol) upon treatment withtert-butyldimethylsilyl chloride (1.67 g, 11.04 mmol) and imidazole (938mg, 13.8 mmol) in THF (17 mL) was stirred as thick slurry for 48 h underN₂. The solvent was evaporated, and the crude material was dissolved inMeOH (10 mL). The resulting solution was stirred at rt for 2 h. Thesolvent was evaporated, and the crude material was diluted with CH₂Cl₂(50 mL) and treated with 0.1N HCl (2×10 mL). The CH₂Cl₂layer was washedwith brine and dried over MgSO₄. Removal of the volatiles gave titlecompound as an oil (1.8 g), which was used without further purification(LC/Mass, + ion): 334 (M+H).

To a stirred solution of Step 1 compound (333 mg, 1.0 mmol) in 6 mL ofCH₂Cl₂ was added 1-[3-(dimethylamino)-propyl]-3-ethylcarbodiimidehydrochloride (256 mg, 1.32 mmol). The solution was then stirred at rtfor 30 min, followed by addition with Example 6 Step 3 amine TFA salt(160 mg, 0.66 mmol) and 4-(dimethylamino)pyridine (244 mg, 2.0 mmol).The solution was then stirred at rt overnight. The mixture was dilutedwith CH₂Cl₂ (5 mL) and washed sequentially with H₂O, 10% citric acid,brine, then dried over Na₂SO₄ and evaporated to give the title compound(350 mg) which was used without further purification (LC/Mass, + ion):442 (M+H).

An oven-dried 10-mL round bottomed flask was charged with Step 2compound (350 mg, 0.79 mmol), imidazole (108 mg, 1.58 mmol), pyridine (3mL). The flask under argon was cooled to −30° C. Slow addition of POCl₃(0.30 mL, 3.16 mmol) gave after mixing a thick slurry. The slurry wasmixed at −30° C. for 3 h and the volatiles evaporated. Dichloromethane(5 mL) was then added and the insoluble solid was removed by filtration.The organic layer was washed with H₂O, 10% citric acid, brine and driedover Na₂SO₄. Removal of solvent gave crude desired nitrile (330 mg)(LC/Mass, + ion): 424 (M+H).

Trifluoroacetic acid (3.3 mL) was added to a stirred solution of Step 3compound (330 mg, 0.58 mmol) in 3.3 mL CH₂Cl₂. The solution was thenstirred at rt for 30 min, a few drops of water were added and themixture mixture stirred for 0.5 h. The mixture was diluted with CH₂Cl₂(5 mL) and concentrated under reduced pressure to a thick oil. Theproduct was purified by reverse phase preparative column chromatographyon a YMC S5 ODS 20×100 mm column to give the title compound, 59 mg, 17%.Purification conditions: gradient elution from 10% methanol/water/0.1TFA to 90% methanol/water/ 0.1 TFA over 15 min; 5 min hold at 90%methanol/water/0.1 TFA. Flow rate: 20 mL/min. Detection wavelength: 220.Retention Time 10 Min. (LC/Mass, + ion): 210 (M+H).

General Method B: Claisen rearrangement sequence to Boc-protected aminoacids.

General method B affords the quaternary Boc-protected amino acids.Examples 30-47 contain the vinyl sidechain by coupling amino acids ofwhich Scheme 4, compound 20 is representative. Cyclopentanone wasolefinated under Horner-Emmons conditions to afford 17 which was reducedto the allylic alcohol 18 using DIBAL-H in toluene −78° C. to rt.Allylic alcohol 18 was esterified with N-Boc glycine using DCC/DMAP inCH₂Cl₂ to give 19. Glycine ester 19 was subjected to a Lewis acidmediated Claisen rearrangement by complexation with anhydrous zincchloride and deprotonation at −78° C. with lithium diisopropylamidefollowed by warming to ambient temperature to afford 20.

Step 1

Cyclopentylideneacetic Acid Ethyl Ester

To a flame-dried 500-mL round-bottomed flask containing NaH (5.10 g of a60% dispersion in mineral oil, 128 mmol, 1.10 equiv) in 120 mL anhydrousTHF at 0° C. under argon was added triethylphosphonoacetate (25.6 mL,128 mmol, 1.10 equiv) dropwise through an addition funnel. The mixturewas allowed to warm to rt, stirring for an additional 1 h. A solution ofcyclopentanone (10.3 mL, 116 mmol) in 10 mL anhydrous THF was addeddropwise over 20 min through an addition funnel, and the mixture wasallowed to stir at rt for 2.5 h. Ether (200 mL) and water (100 mL) werethen added, and the layers were separated. The organic phase was washedsuccessively with water (100 mL) and brine (100 mL), dried (Na₂SO₄), andconcentrated under reduced pressure, giving 17.5 g (98%) of the desiredester as a colorless oil.

Step 2

2-Cyclopentylideneethanol

To a flame-dried 500-mL round-bottomed flask containingcyclopentylideneacetic acid ethyl ester (17.5 g, 113 mmol) in 100 mLanhydrous toluene at −78° C. under argon was added DIBAL-H (189 mL of a1.5 M solution in toluene, 284 mmol, 2.50 equiv) dropwise over a 30 minperiod through an addition funnel, and the mixture was then allowed towarm to rt, stirring for 18 h. The reaction mixture was then recooled to−78° C., and quenched by the careful addition of 30 mL anhydrous MeOH.Upon warming to rt, 1 N Rochelle's salt (100 mL) was added, and themixture was stirred 90 min. The biphasic reaction mixture was thendiluted with Et₂O (200 mL) in a separatory funnel, and the layers wereseparated. The organic layer was then washed with brine (100 mL), dried(Na₂SO₄), and concentrated under reduced pressure. Purification by flashcolumn chromatography (silica gel, CH₂Cl₂/EtOAc, 10:1) gave 11.6 g (92%)of the desired allylic alcohol as a colorless oil.

Step 3

(2-Cyclopentylideneethyl)-N-(tert-Butyloxycarbonyl) glycinate

To a flame-dried 500-mL round-bottomed flask containingN-(tert-butyloxycarbonyl)glycine (13.45 g, 76.75 mmol) in 100 mL CH₂Cl₂at rt was added Step 2 compound 8.61 g, 76.75 mmol, 1.00 equiv) in 20 mLCH₂Cl₂, followed by dicyclohexylcarbodiimide (16.63 g, mmol, 1.05 equiv)in 80 mL CH₂Cl₂. To this reaction mixture was then added4-dimethylaminopyridine (0.94 mg, mmol, 0.10 equiv), and the mixture wasallowed to stir overnight. The reaction mixture was then filteredthrough a medium sintered-glass funnel, rinsing with 100 mL CH₂Cl₂, andconcentrated under reduced pressure. The crude product was then purifiedby flash chromatography (silica gel, hexanes/EtOAc, 20:1 to 1:1gradient) to give 19.43 g (94%) of the desired glycinyl ester as acolorless oil.

Step 4

N-(tert-Butyloxycarbonyl)(1′vinylcyclopentyl)-glycine

A flame-dried 500-mL round-bottomed flask under argon was charged withZnCl₂ (11.8 g, mmol, 1.20 equiv) and 20 mL toluene. The mixture washeated under vacuum with vigorous stirring to azeotrope off any tracesof moisture with the distilling toluene, repeating this process (2 ×).The flask was then cooled to rt under argon, (2-cyclopentylideneethyl)N-(tert-butyloxycarbonyl)glycinate (19.36 g, 71.88 mmol) was added viacannula as a solution in 180 mL THF, and the mixture was then cooled to−78° C. In a separate flame-dried 200-mL round-bottomed flask containingdiisopropylamine (26.3 mL, mmol, 2.60 equiv) in 90 mL THF at −78° C. wasadded n-butyllithium (71.89 mL of a 2.5 M solution in hexanes, mmol, 2.5equiv), and the mixture was allowed to warm to 0° C. for 30 min beforerecooling to −78° C. The lithium diisopropylamine thus generated wasthen added via cannula to the ZnCl₂ ester mixture dropwise at a steadyrate over 40 min, and the resultant reaction mixture was allowed toslowly warm to rt and stir overnight. The yellow reaction mixture wasthen poured into a separatory funnel, diluted with 300 mL Et₂O, and theresultant organic solution was washed successively with 300 mL 1N HCland 300 mL brine, dried (Na₂SO₄), and concentrated under reducedpressure. Purification by flash chromatography (silica gel, 3% MeOH inCH₂Cl₂ with 0.5% HOAc) gave 17.8 g (92%) of the desired amino acidproduct as a white solid. (FAB MH+270).

EXAMPLE 30

General Method C: Peptide coupling to 4,5-methanoprolinamide, amidedehydration and final deprotection.

The TFA salt of amide 13 was coupled to a variety of racemic quaternaryprotected amino acids using HOBT/EDC in DMF at rt to give a D/L mixtureof diastereomers at the N-terminal amino acid. The desired Ldiastereomer was chromatographically isolated either as the amide 21 oras the nitrile 22. Nitrile 22 was obtained by treatment of the amidewith POCl₃/imidazole in pyridine at −20° C. The final target 23 wasobtained by deprotection under acidic conditions using TFA in CH₂Cl₂.

Example 6 Step 3 compound (877 mg, 3.65 mmol) and N-Boccyclopentylvinylamino acid, described in Step 4 of general method B(1.13 g, 4.20 mmol) were dissolved in 20 mL anhydrous DMF, cooled to 0°C. and to this mixture was added EDAC (1.62 g, 8.4 mmol), HOBT hydrate(2.54 g, 12.6 mmol, and TEA (1.27 g, 12.6 mmol) and the reaction wasallowed to warm to rt and stirred for 24 h. The reaction mixture wastaken up in EtOAc (100 mL), washed with H₂O (3×20 mL), dried (Na₂SO₄),and purified by silica gel flash column chromatography (100% EtOAc) togive 1.38 g (86%) of Step 1 compound (MH+, 378).

Step 1 compound (1.38 g, 3.65 mmol) and imidazole (497 mg, 7.30 mmol)were dried by toluene azeotrope (5 mL×2), dissolved in 10 mL anhydrouspyridine, cooled to −30° C. under nitrogen gas and POCl₃ (2.23 g, 14.60mmol) was added by syringe. The reaction was complete after 1 h and wasevaporated to dryness and the remainder purified by two sequential flashcolumn chromatographies over silica gel. The first column (100% EtOAc)was used to isolate the mixture of diastereomers (1.15 g, 88%) from theby-products of the reaction. The second column (gradient of 25%EtOAC/hexanes to 50% EtOAc/hexanes) was run to resolve the mixture ofdiastereomers and provided 504 mg of the desired Step 2 nitrile(MH+360).

Step 2 compound (32 mg, 0.09 mmol) was dissolved in 1 mL of CH₂Cl₂ and 1mL of TFA was added and the reaction stirred for 30 min at rt and wasevaporated to dryness. The product was purified by reverse phasepreparative column chromatography on a YMC S5 ODS 20×250 mm column togive 12 mg of the TFA salt (lyophilized from water or isolated afterevaporation of eluent and trituration with ether) the title compound.Purification conditions: gradient elution from 10% methanol/water/0.1TFA to 90% methanol/water/0.1 TFA over 18 min; 5 min. hold at 90%water/0.1 trifluoroacetic acid. Flow rate: 20 mL/min. Detectionwavelength: 220.

Examples 30-39 were prepared by the methods outlined in General Method Band General Method C starting from cyclopentanone, cyclobutanone,cyclohexanone, cycloheptanone, cyclooctanone,cis-3,4-dimethylcyclopentanone, and 4-pyranone,cyclopropaneethylhemiacetal, acetone, and 3-pentanone respectively.

TABLE 2

MS Example R [M + H] 30

260 31

246 32

274 33

288 34

302 35

288 36

276  37*

232 38

234 39

262 *Step 3 compound was prepared by the method described in TetrahedronLetters 1986, 1281-1284.

EXAMPLE 40

Step 1 compound was prepared employing general method B starting fromcyclopentanone and 2-fluorotriethylphos-phonoacetate instead oftriethylphosphonoacetate.

Title compound was prepared by the peptide coupling of Step 1 acidfollowed by dehydration and final deprotection as described in generalmethod C [MS (M+H) 278].

EXAMPLE 41

Step 1 compound was prepared employing general method B starting fromcyclobutanone and 2-fluorotriethylphos-phonoacetate instead oftriethylphosphonoacetate.

Title compound was prepared by the peptide coupling of Step 1 acidfollowed by dehydration and final deprotection as described in generalmethod C. MS (M+H) 264.

EXAMPLE 42

Step 1 compound was prepared employing general method B starting fromcyclopentanone and triethylphosphono propionate instead oftriethylphosphonoacetate.

Title compound was prepared by the peptide coupling of Step 1 acidfollowed by dehydration and final deprotection as described in generalmethod C. MS (M+H) 274

EXAMPLE 43

Step 1 compound was prepared employing general method B starting fromcyclobutanone and triethylphosphono propionate instead oftriethylphosphonoacetate.

Title compound was prepared by the peptide coupling of Step 1 acidfollowed by dehydration and final deprotection as described in generalmethod C. MS (M+H) 260.

EXAMPLE 44

General Method D: Oxidative cleavage of vinyl substituent by ozonolysis.The protected cyclopentylvinyl nitrile 22 was treated with ozone for 6-8min and subjected to a reductive quench with sodium borohydride tofurnish the hydroxymethyl analog 24 directly. This compound wasdeprotected under acidic conditions with TFA in CH₂Cl₂ at 0° C. to givethe target compound 25.

Cyclopentylvinyl compound prepared in Step 2 of general method C (1.28g, 3.60 mmol) was dissolved in 56 mL of a 2:5 mixture ofCH₂Cl₂:methanol, cooled to —78° C. and was treated with a stream ofozone until the reaction mixture took on a blue color, at which time,NaBH₄ (566 mg, 15.0 mmol, 4.2 equiv) was added and the reaction waswarmed to 0° C. After 30 min, the reaction was quenched with 2 mLsaturated aqueous NaHCO₃ and then warmed to rt. The reaction mixture wasevaporated to dryness and taken up in EtOAc. A small amount of water wasadded to dissolve the inorganics and the layers separated. The EtOAclayer was dried (Na₂SO₄), filtered and evaporated to an oil that waspurified by flash column chromatography on silica gel with EtOAc to give922 mg (71%) of Step 1 compound. MS(M+H)364.

Step 1 compound (900 mg, 2.48 mmol) was dissolved in 60 mL of CH₂Cl₂,cooled to 0° C. and treated with 20 mL of freshly distilled TFA. Thereaction was complete in 80 min and the mixture was evaporated todryness and purified by preparative HPLC (YMC S5 ODS 30×100 mm, 18minute gradient 80% Solv A:Solv B to 100% Solv B, Solvent A=10%MeOH-90%H₂O-0.1% TFA, Solvent B=90% MeOH-10% H₂O -0.1% TFA, collectedproduct from 5.1-6.5 min) to give, after lyophillization from water, 660mg (71%) of title compound, TFA salt as a white lyophillate. (MH+264).

EXAMPLE 45

General Method E: Oxidative cleavage of vinyl substituent by osmiumtetroxide-sodium periodate followed by sodium borohydride reduction toalcohol. The cyclobutylolefin 26 was treated with osmium tetroxide andsodium periodate in THF:water, 1:1, and the intermediate aldehyde wasisolated crude and immediately reduced with sodium borohydride to give27 in 56% yield. Standard deprotection conditions using TFA afforded thetarget compound 28.

N-Boc protected cyclobutylvinyl compound (Example 31, prepared bygeneral method C) (0.16 g, 0.46 mmol) was dissolved in 10 mL of a 1:1mixture of THF:water and treated with OsO4 (12 mg, catalyst) and NaIO₄(0.59 g, 2.76 mmol, 6 equiv). After 2 h, the reaction mixture wasdiluted with 50 mL of ether and 10 mL of water. The layers wereequilibrated and the organic fraction was washed one time with NaHCO₃solution, dried over MgSO₄ and concentrated to give a dark oil. The oilwas diluted with 10 mL of methanol and treated with NaBH₄ (0.08 g, 2.0mmol). The mixture turned very dark and after 30 min was diluted withether and the reaction was quenched with aqueous NaHCO₃ solution. Themixture was equilibrated and layers separated. The organic fraction waswashed with solutions of NaHCO₃ and 0.1 M HCl. The organics were dried(MgSO₄) and concentrated to give 90 mg (56%) of the Step 1 compound as adark oil.

Step 1 compound (90 mg, 0.26 mmol) was dissolved in 3 mL of CH₂Cl₂,cooled to 0° C. and treated with 3 mL of freshly distilled TFA. Thereaction was complete in 80 min and evaporated to dryness and purifiedby preparative HPLC (YMC S5 ODS 30×100 mm, 10 minute gradient 100%A to100% B, Solvent A=10% MeOH-90%H20O-0.1% TFA, Solvent B=90% MeOH-10%H₂O-0.1% TFA, to give, after removal of water, 50 mg (60%) of titlecompound. (MH+250).

TABLE 3

Method of Example R Preparation [M + H] 44

Ozonolysis/borohydride 264 45

Osmium/periodate/ borohydride 250 46

Ozonolysis/borohydride 278 47

Osmium/periodate/ borohydride 292 48

Ozonolysis/borohydride 292

EXAMPLE 49

Part A. A 50-mL flask was charged withdihydro-4,4-dimethyl-2,3-furandione (5.0 g, 39.0 mmol), acetic acid (10mL), sodium acetate (3.82 g, 39.0 mmol) and hydroxylamine hydrochloride(2.71 g, 39.0 mmol). The reaction mixture was stirred for 2 h at rt andconcentrated under reduced pressure to remove most of the acetic acid.The remainder was poured into water (100 mL) and the aqueous phaseextracted with EtOAc (3×40 mL). The organics were dried over Na₂SO₄ andconcentrated to a colorless oil which solidified on standing.

Part B. A 200-mL round bottomed flask was charged with Part A solid (@39 mmol) and diluted with 80 mL of ethanol and 39 mL of 2N HCl (78mmol). The mixture was treated with 1.0 g of 5% Pd/carbon and themixture degassed. The flask was placed under an atmosphere of H₂ for 8h. The mixture was filtered through celite and the filtrate concentratedto an off white solid.

Part C. A 250-mL round bottomed flask was charged with Part B solid anddiluted with THF (50 mL) and water (15 mL). The mixture was treated withdi-tert-butyldicarbonate (12.7 g, 117 mmol) and sodium bicarbonate (10.0g, 117 mmol). After 4 h of stirring the mixture was diluted with 50 mLof ether and 50 mL of water. The layers were separated and the organicfraction dried over MgSO₄ and concentrated. The residue was purified byflash column chromatography on silica gel with 30% EtOAc in hexanes togive 2.00 g (22% overall) of Step 1 compound as a white solid.

To a stirred solution of Step 1 compound (1.00 g, 3.80 mmol) in THF (20mL) at rt under nitrogen was added LiOH hydrate (0.16 g, 3.80 mmol) andthen water (5 mL). The reaction was stirred at 40° C. for 0.5 h and thencooled to rt. The mixture was concentrated to dryness and the remainderwas stripped from THF (2×), toluene (2×) and THF (1×). The remainingglass was diluted with 5 mL of THF and treated with imidazole (0.63 g,9.19 mmol) followed by t-butyl-dimethylsilyl chloride (1.26 g, 8.36mmol). The reaction was stirred overnight and quenched with 10 mL ofmethanol. After 1 h of stirring the mixture was concentrated. Anadditional portion of methanol was added and the mixture concentrated.The oil was diluted with ether and 0.1 N HCl (pH 2). The layers wereequilibrated and aqueous drawn off. The organic fraction was dried overMgSO₄ and concentrated to give 1.25 g (83%) of Step 2 compound as acolorless glass.

The Title compound was prepared by the peptide coupling of Step 2carboxylic acid with Example 6 Step 3 amine, followed by dehydration anddeprotection as outlined in General Method C. MS (M+H) 238.

General Method F: Catalytic Hydrogenation of vinyl substituent. As shownin Scheme 8, the protected vinyl substituted amino acid 20 wastransformed to the corresponding saturated analog 29 by catalytichydrogenation using 10% Pd/C and hydrogen at atmospheric pressure.

Step 1.

The N-(tert-Butyloxycarbonyl)(1′vinylcyclopentyl) glycine (2.23 g, 8.30mmol) was dissolved in 50 mL MeOH and placed in a hydrogenation vesselpurged with argon. To this mixture was added 10% Pd-C (224 mg, 10% w/w)and the reaction stirred under 1 atm H₂ at rt for 12 h. The reaction wasfiltered through celite and concentrated and purified by flash columnchromatography on silica gel with 1:9 methanol:CH₂Cl₂ to give the Step 1compound as a glass. (FAB MH+272)

Examples 50-56 were prepared by the peptide coupling of amino acids(where the vinyl substituent has been hydrogenated according to generalmethod F) followed by dehydration and deprotection as described ingeneral method C.

TABLE 4

MS Example R1, R2 [M + H] 50 Cyclopentyl 262 51 cyclobutyl 248 52cycloheptyl 290 53 4-pyranyl 278 54 methyl, methyl 236 55 ethyl, ethyl264 56 methyl, ethyl 250

EXAMPLE 57

The title compound in Example 57 was prepared by the peptide coupling ofthe isopropyl cyclobutane amino acid (where the olefin substituent hasbeen hydrogenated according to general method F) followed by dehydrationand deprotection as described in general method C.

EXAMPLE 58

The title compound in Example 58 was prepared by the peptide coupling ofthe isopropyl cyclopentane amino acid (where the olefin substituent hasbeen hydrogenated according to general method F) followed by dehydrationand deprotection as described in general method C. MS (M+H) 276

General Method G: L-Amino acids synthesized by Asymmetric StreckerReaction. Commercially available adamantyl carboxylic acid wasesterified either in MeOH with HCl at reflux or usingtrimethylsilyldiazomethane in Et₂O/methanol to give 30. The ester wasreduced to the alcohol 31 with LAH in THF and then subjected to a Swernoxidation to give aldehyde 32. Aldehyde 32 was transformed to 33 underasymmetric Strecker conditions with KCN, NaHSO₃ andR-(−)-2-phenylglycinol. The nitrile of 33 was hydrolyzed under stronglyacidic conditions using 12M HCl in HOAc to give 34. The chiral auxiliarywas removed by catalytic reduction using Pearlman's catalyst in acidicmethanol under 50 psi hydrogen to give 35 and the resulting amino groupwas protected as the t-butylcarbamate to give 36.

Adamantane-1-carboxylic acid (10.0 g, 55 mmol, 1 equiv) was dissolved ina mixture of Et₂O (160 mL) and MeOH (40 mL), and was treated withtrimethylsilyl diazomethane (2.0 M in hexane, 30 mL, 60 mmol, 1.1 equiv)and stirred at rt for 3 h. The volatiles were then removed by rotaryevaporation and the product purified by flash column chromatography onsilica gel (5×15 cm) with 40% CH₂Cl₂/hexanes to give the product as awhite crystalline solid (10.7 g, 100%).

Step 1 compound (10.7 g, 0.055 mmol, 1 equiv) was dissolved in anhydrousTHF (150 mL) under argon and was treated with a solution of LiAlH₄ (1 Min THF, 69 mL, 69 mmol, 1.25 equiv). After stirring at rt for 1.5 h, thereaction was cooled to 0° C. and quenched sequentially with H₂O (5.1mL), 15% aq NaOH (5.1 mL), and H₂O (10.2 mL). After stirring at rt for15 min, the slurry was vacuum filtered, and the solids washed with EtOAc(2×100 mL). The filtrate was concentrated by rotary evaporation and theresulting solid purified by flash column chromatography on silica gel(5×15 cm) with 10% EtOAc/CH₂Cl₂. This afforded the Step 2 product as awhite solid (8.74 g, 96%).

An oven-dried 3-neck flask equipped with 125-mL addition funnel wascharged with anhydrous CH₂Cl₂ (150 mL) and anhydrous DMSO (10.3 mL,0.145 mol, 2.5 equiv) under argon atmosphere and cooled to −78° C. Slowdropwise addition of oxalyl chloride (6.7 mL, 0.0768 mol, 1.32 equiv)followed by stirring for 15 min provided an activated DMSO adduct. Thiswas treated with a solution of Step 2 compound (9.67 g, 58.2 mmol, 1equiv) in dry CH₂Cl₂ (75 mL) and the reaction allowed to stir for 1 h.The resulting white mixture was then treated dropwise with triethylamine(40.5 mL, 0.291 mol, 5 equiv). After 30 min, the cooling bath wasremoved, and the reaction quenched sequentially with cold 20% aq KH₂PO₄(25 mL) and cold H₂O (150 mL). After stirring at rt for 15 min themixture was diluted with Et₂O (400 mL)and the layers were separated. Theorganics were washed organic with cold 10% aq KH₂PO₄ (3×150 mL) and satdaq NaCl (100 mL). The organics were dried (Na₂SO₄), filtered andconcentrated. The residue was purified by flash column chromatography onsilica gel (5×10 cm) with CH₂Cl₂ to give the Step 3 compound as a whitesolid (9.40 g, 98%).

Step 3 compound (9.40 g, 57 mmol, 1 equiv) was suspended in H₂O (145 mL)and cooled to 0° C. The mixture was treated with NaHSO₃ (5.95 g, 57mmol, 1 equiv), KCN (4.0 g, 59 mmol, 1.04 equiv), and a solution of(R)-(−)-phenylglycinol (8.01 g, 57 mmol, 1 equiv) in MeOH (55 mL). Theresulting mixture was stirred at rt for 2 h, then refluxed for 16 h. Themixture was cooled to rt, and 200 mL of EtOAc added. After mixing for 15min the layers were separated. The aqueous fraction was extracted withEtOAc. The combined EtOAc extracts were washed with brine (50 mL), driedover anhydrous Na₂SO₄, filtered and the filtrate concentrated. Theproduct was purified by flash column chromatography on silica gel(6.4×20 cm) with 20% EtOAc/hexanes to give the desired (R,S) product asa white solid (11.6 g, 37.4 mmol, 65%): MS m/e 311 (M+H)⁺.

The Step 4 nitrile (5.65 g, 18 mmol) was heated in conc. HCl (120 mL)and HOAc (30 mL) at 80° C. for 18 h, at which time the reaction wascooled in an ice bath. Vacuum filtration of the resulting precipitateafforded the desired product as a white solid (5.21 g, 14 mmol, 78%). MSm/e 330 (m+H)⁺.

The Step 6 compound (5.21 g, 14 mmol) was dissolved in MeOH (50 mL) andHOAc (10 mL), and hydrogenated with H₂ (50 psi) and Pearlman's catalyst(20% Pd(OH)₂, 1.04 g, 20% w/w) for 18 h. The reaction was filteredthrough a PTFE membrane filter and the catalyst washed with MeOH (3×25mL). The filtrate was concentrated by rotary evaporation to afford awhite solid. The product was used in Step 7 without furtherpurification.

The crude Step 6 compound (@ 14 mmol) was dissolved in anhydrous DMF (50mL) under argon and treated with K₂CO₃ (5.90 g, 42 mmol, 3 equiv) anddi-tert-butyldicarbonate (3.14 g, 14 mmol, 1 equiv) under argon at rt.After 19 h, the DMF was removed by rotary evaporation (pump) and theresidue dried further under reduced pressure. The residue was mixed withH₂O (100 mL) and Et₂O (100 mL), the layers separated, and the alkalineaqueous with Et₂O (2×100 mL) to remove the by-product from thehydrogenolysis step. The aqueous was cooled to 0° C., diluted with EtOAc(200 mL), and stirred vigorously while care fully acidifying the aqueousto pH 3 with 1N aq HCl. The layers separated and the aqueous extractedwith EtOAc (100 mL). The combined EtOAc extracts were washed with brine(50 mL), dried (Na₂SO₄), filtered and the filtrate concentrated byrotary evaporation. The residue was purified by SiO₂ flash column (5×12cm) with 5% MeOH/CH₂Cl₂+0.5% HOAc. The product was chased with hexanesto afford the product as a white foam (4.07 g, 13 mmol, 92%): MS m/e 310(m+H)⁺.

EXAMPLE 59

The title compound in Example 59 was prepared by the peptide coupling ofthe Step 7 compound in general method G followed by dehydration anddeprotection as described in general method C.MS m/e 300 (m+H)⁺.

EXAMPLE 60

A solution of KMnO₄ (337 mg, 2.13 mmol, 1.1 equiv) in 2% aq KOH (6 mL)was heated to 60° C. and Step 7 compound in general method G (600 mg,1.94 mmol, 1 equiv) was added in portions, and heating increased to 90°C. After 1.5 h, the reaction was cooled to 0° C., EtOAc (50 mL) wasadded, and the mixture was carefully acidified to pH 3 with 1N HCl. Thelayers were separated and the aqueous was extracted with EtOAc (50 mL).The combined organic extracts were washed with brine, dried over Na₂SO₄,filtered and concentrated. The residue was purified by flash columnchromatography on silica gel (3.8×15 cm) with 2% (200 mL), 3% (200 mL),4% (200 mL), and 5% (500 mL) MeOH/CH₂Cl₂+0.5% HOAc. After isolation ofthe product, the material was chased with hexanes to afford a whitesolid (324 mg, 51%): MS m/e 326 (m+H)⁺.

The Step 1 compound (404 mg, 1.24 mmol, 1 equiv) was dissolved inanhydrous DMF (10 mL) under argon and cooled to 0° C. The following wereadded in order: Example 6 Step 3 salt (328 mg, 1.37 mmol, 1.1 equiv),HOBT (520 mg, 3.85 mmol, 3.1 equiv), EDAC (510 mg, 2.61 mmol, 2.1equiv), and TEA (0.54 mL, 3.85 mmol, 3.1 equiv). The reaction mixturewas allowed to warm to rt overnight and the DMF removed by rotaryevaporation (pump). The remainder was dried further under vacuum. Theresidue was dissolved in EtOAc (100 mL), washed with satd aq NaHCO₃ (50mL) and satd aq NaCl (25 mL), dried over anhydrous Na₂SO₄, filtered andconcentrated by rotary evaporation. The product was purified flashcolumn chromatography on silica gel (3.8×15 cm) with a gradient of 6%(200 mL), 7% (200 mL), and 8% (500 mL) MeOH/CH₂Cl₂ to give the productas a white solid (460 mg, 1.06 mmol, 85%): MS m/e 434 (m+H)⁺.

The Step 2 compound (95 mg, 0.22 mmol, 1 equiv) was dissolved inanhydrous CH₂Cl₂ (2.5 mL) under argon and cooled to −78° C. The mixturewas treated with diisopropylethylamine (65 μL, 0.37 mmol, 1.7 equiv),and triethylsilyl triflate (75 μL, 0.33 mmol, 1.5 equiv), and stirred at0° C. for 1.5 h. The reaction was mixed with MeOH (0.5 mL), silica gel(200 mg) and H₂O (2 drops) and stirred at rt for 18 h. The solvent wasremoved by rotary evaporation and the residue purified flash columnchromatography on silica gel(2.5×10 cm) with 4% MeOH/CH₂Cl₂ to affordthe product (92 mg, 0.17 mmol, 77%): Ms m/e 540 (m+H)⁺.

The Step 3 compound (90 mg, 0.16 mmol, 1 equiv) was dissolved inanhydrous pyridine (2 mL) under argon and cooled to −30° C. Treatmentwith imidazole (24 mg, 0.35 mmol, 2.1 equiv) and phosphorous oxychloride(66 μL, 0.67 mmol, 4.1 equiv), and continued stirring at −30° C. for 45min gave a thick slurry. Volatiles were by rotary evaporation and thecake dried further under reduced pressure. The product was purified byflash column chromatography on silica gel (2.5×10 cm) with 7%EtOAc/CH₂Cl₂ to afford the product as a white foam (76 mg, 87%): MS m/e530 (m+H)⁺

The Step 4 compound (76 mg, 0.14 mmol) was dissolved in anhydrous CH₂Cl₂(1 mL) and cooled to 0° C. and treated with TFA (1 mL) and H₂O (2 drops)and stirred for 1.5 hr at 0° C. The solvents were removed by rotaryevaporation and the residue was chased with toluene (5 mL) and driedunder reduced pressure. Trituration with Et₂O afforded the titlecompound as a white solid (54 mg, 88%): MS m/e 316 (m+H)⁺.

EXAMPLE 61

An oven-dried flask purged with argon was charged with anhydrous CH₂Cl₂(3 mL) and cooled to −78° C. Treatment with diethylaminosulfurtrifluoride (DAST, 60 μL, 0.45 mmol, 1.5 equiv), followed by a solutionof the Example 60 Step 2 compound (131 mg, 0.30 mmol, 1 equiv) in dryCH₂Cl₂ (3 mL). After 15 min, the reaction was poured into a separatoryfunnel containing satd aq NaHCO₃ (25 mL) and the layers were separated.The aqueous fraction was extracted with CH₂Cl₂ (25 mL), then thecombined organic extracts were washed with brine (10 mL), dried(Na₂SO₄), filtered and concentrated. The product was purified by flashcolumn chromatography on silica gel (2.5×10 cm) with 5% MeOH/CH₂Cl₂ togive Step 1 compound (124 mg, 0.29 mmol, 94%): MS m/e 436 (m+H)⁺.

The fluorinated amide from Step 1 (161 mg, 0.37 mmol, 1 equiv) wasdissolved in anhydrous pyridine (4 mL) under argon and cooled to −30° C.The mixture was treated with imidazole (54 mg, 0.77 mmol, 2.1 equiv) andphosphorous oxychloride (143 μL, 1.52 mmol, 4.1 equiv) and stirred at−30° C. for 40 min. The solvent was removed by rotary evaporation anddried further under reduced pressure. The product was purified by flashcolumn chromatography on silica gel (2.5×10 cm) with 5% EtOAc/CH₂Cl₂ togive the Step 2 compound as a white foam (126 mg, 82%): MS m/e 418(m+H)⁺.

The Step 2 compound (125 mg, 0.30 mmol) was dissolved in TFA/CH₂Cl₂ (1:1v/v, 2 mL), and stirred at rt. After 30 min, the solvents were removedby rotary evaporation, the remainder was chased with toluene (2×5 mL),and the solid dried under reduced pressure. Trituration with Et₂Oafforded the title compound as a white solid (93 mg, 0.21 mmol, 72%): MSm/e 318 (m+H)⁺.

EXAMPLE 62

The Step 1 compound was prepared beginning with 2-adamantanal andelaborated to the homochiral Boc-amino acid by an asymmetric Streckersynthesis according to general method G.

The title compound in Example 62 was prepared by the peptide coupling ofthe 2-adamantyl amino acid described in Step 1 followed by dehydrationand deprotection as described in general method C.MS (M+H) 300.

EXAMPLE 63

An oven-dried flask equipped with a condenser and drying tube wascharged with norbornane-2-carboxylic acid (4.92 g, 35 mmol, 1 equiv) andtreated with bromine (2.1 mL, 41 mmol, 1.15 equiv) and phosphoroustrichloride (0.153 mL, 1.8 mmol, 0.05 equiv). The mixture was heated at85° C. for 7 h protected from light. Additional bromine (0.4 mL, 7.8mmol, 0.22 equiv) was added with continued heating for 1 h. The mixturewas cooled to rt, and Et₂O (100 mL) was added. The mixture was washedwith 10% aq NaHS0₃ (50 mL), H₂O (2×50 mL), and brine (25 mL). The etherfraction was dried (Na₂SO₄), filtered and concentrated by rotaryevaporation. The product was purified by flash column chromatography onsilica gel (5×15 cm) with 2% to 4% MeOH/CH₂Cl₂+0.5% HOAc. The productwas chased with hexanes to remove residual HOAc. The isolated materialconsists of two inseparable materials (4.7 g), which was used withoutfurther purification in the next step.

The crude product from above, exo-2-bromonorbornane-1-carboxylic acid(4.7 g, impure) in Et₂O (80 mL) and MeOH (20 mL), was mixed withtrimethylsilyldiazomethane (2.0 M in hexane, 11.8 mL, 23.6 mol), andstirred at rt for 1 h. Solvent was removed by rotary evaporation, andpurification of the oil by flash column chromatography on silica gel(5×18 cm) with a gradient of CH₂Cl₂/hexanes (600 mL each of 20% and 30%)followed by CH₂Cl₂ afforded the product as a white solid (3.97 g, 0.017mol, 79% for 2 steps): MS m/e 233/235 (m+H)⁺.

Methyl exo-2-bromonorbornane-1-carboxylate (2.0 g, 8.58 mmol, 1 equiv)was dissolved in anhydrous THF (50 mL) in an oven-dried 3-neck flaskequipped with a condenser, and purged with argon. The mixture wastreated with AIBN (288 mg, 1.71 mmol, 0.2 equiv) and tributyltin hydride(3.6 mL, 12.87 mmol, 1.5 equiv), and then heated to reflux for 2 h. Theflask was cooled to rt, and the THF was removed by rotary evaporation togive the crude product. The product was purified by flash columnchromatography on silica gel(5×10 cm) with 5% EtOAc/hexanes. Theresulting material was used in the next step without furtherpurification.

The Step 1 compound was prepared beginning with 1-norbonyl methylcarboxylate and elaborated to the homochiral Boc amino acid by anasymmetric Strecker synthesis according to general method G.

The title compound in Example 63 was prepared by the peptide coupling ofthe 1-norbonyl amino acid described in Step 2, followed by dehydrationand deprotection as described in general method C. MS (M+H) 260.

EXAMPLE 64

The Step 1 compound was prepared beginning with 4-formylpyran andelaborated to the homochiral Boc amino acid by an asymmetric Streckersynthesis according to general method G.

The title compound in Example 64 was prepared by the peptide coupling ofthe 4-pyranyl amino acid described in Step 2, followed by dehydrationand deprotection as described in general method C. MS (M+H) 250.

General Method H: Strecker Synthesis of Racemic Amino Acids.

To a stirred solution of 1-phenylcyclo-1-pentanecarboxylic acid (5.00 g,26.3 mmol) in 25 mL of THF at 0° C. was added LAH (52 mL , 52 mmol, 1M)in THF. The reaction mixture was slowly warmed to rt and then refluxedfor 18 h. The reaction was quenched according to the Fieser procedure:careful addition of 2 mL of water; 6 mL of 15% NaOH in water; and 2 mLof water. The biphasic mixture was diluted with 100 mL of ether and thegranular white solid filtered off. The ether fraction was dried overNa₂SO₄ and evaporated to give 4.30 g (93%) of the Step 1 compound.

To a stirred solution of Step 1 compound (0.80 g, 4.50 mmol) in 15 mL ofCH₂Cl₂ at rt was added celite (5 g) followed by PCC (1.95 g, 5.00 mmol).After stirring for 3 h the reaction mixture was diluted with 40 mL ofCH₂Cl₂ and filtered through celite. The filtrate was filtered anadditional time through silica gel resulting in a colorless filtrate.The CH₂Cl₂ fraction was evaporated to give 0.72 g (91%) of the aldehydeas a colorless oil.

To a 50-mL round-bottomed flask containing Step 2 compound (0.72 g, 4.20mmol) in 8 mL of water at rt was added NaCN (0.20 g, 4.20 mmol) followedby NH₄Cl (0.20 g, 5.00 mmol). To this reaction mixture was then addedmethanol (8 mL) and the mixture was allowed to stir overnight. Thereaction mixture was then extracted with ether (2×15 mL), dried (MgSO₄)and concentrated under reduced pressure to give the crude Streckerproduct.

To a 100-mL round-bottomed flask containing the crude Strecker productwas added 10 mL of HOAc and 10 mL of conc. HCl. The mixture was refluxedovernight. The mixture was concentrated under reduced pressure to give ayellow solid. The solid was triturated with 5 mL of 1:1 mixture of etherand hexanes. The white solid was treated with triethylamine (1.4 mL,9.99 mmol) and di-tert-butyldicarbonate (1.00 g, 4.60 mmol) in 50 mLDMF. After 4 h the pH of the mixture was adjusted to 9 with saturatedNa₂CO₃ soln. After an additional 3 h of stirring the mixture wasextracted with 1:1 ether and hexanes and the aqueous fraction acidifiedto pH 2 with 5% KHSO₄ solution. The aqueous phase was washed with ether(2×40 mL), the organics dried (MgSO₄), and evaporated to an oil that waspurified by silica gel flash chromatography with 8:92 methanol:CH₂Cl₂ togive 0.3 g (23%) of the Boc-protected amino acid as a light oil (M-H,318).

EXAMPLE 65

The synthesis of the Step 1 compound was described in general method Hfor the Strecker synthesis of racemic amino acids.

The title compound in Example 65 was prepared by the peptide coupling ofthe cyclopentylphenyl amino acid described in Step 1 and general methodH followed by dehydration and deprotection as described in generalmethod C. MS (M+H) 310.

EXAMPLE 66

Step 1 compound was prepared using racemic Strecker synthesis accordingto general method H starting from 2,2-dimethyl-phenylacetic acid.

The title compound in Example 66 was prepared by the peptide coupling ofthe dimethylphenyl amino acid described in step 1 followed bydehydration and deprotection as described in general method C. MS (M+H)284.

EXAMPLE 67

N-(Benzyloxycarbonyl)succinimide (5.6 g, 22.4 mmol) was dissolved inCH₂Cl₂ (25 mL) and the solution was added to a cooled (0° C.) andstirred solution of diethyl aminomalonate hydrochloride (5.0 g, 23.6mmol) and triethylamine (13.4 mL, 95 mmol) in CH₂Cl₂ (125 ml). Theresulting solution was stirred at 0° C. for 10 min and then at rt for 1h. The solution was washed with 10% citric acid (2×50 mL),10% sodiumhydrogen carbonate (2×50 mL), and water (50 mL) and was then dried(Na₂SO₄) and evaporated to afford diethylN-benzyloxycarbonylaminomalonate as a colorless oil, which crystallizedupon standing at 0° C. (6.3 g) (LC/Mass + ion): 310 (M+H).

Step 1 compound (6.18 g, 20 mmol) was dissolved in dry ethanol (30 mL)and added to a solution of sodium ethoxide (2.85 g, 8.8 m mol; 21% w/wsolution in ethanol (6 mL). A solution of 3-methyl-2-butenal (1.68 g, 20mmol) in ethanol (12 mL) was added, and the solution stirred at 25° C.for 24 h. Acetic acid (0.56 mL) was then added the solution hydrogenatedat 50 psi for 24 h using 10% Pd/C (2.0 g) as catalyst. The solution wasfiltered, evaporated and the residue chromatographed on silica withCH₂Cl₂ /EtOAc (9:1) to give 2,2-dicarboethoxy-3,3-dimethyl-pyrrolidine(1.6 g) (LC/Mass, +ion): 244 (M+H).

This diester (850 mg) was refluxed in 5 M hydrochloric acid (10 mL)/TFA(1 mL) for 8 h to give, after evaporation, a powdery white solid.Crystallization from methanol/ether gave 3,3-dimethyl-dl-prolinehydrochloride (190 mg) as white crystals mp 110-112° C.

Step 2 compound (173 mg, 0.97 mmol) was dissolved in DMF (3 mL)/water (3mL). To this clear solution was added triethylamine (0.46 mL, 3.18 mmol)and di-t-butyl dicarbonate (0.23 g, 1.06 mmol), and the reaction mixturewas stirred at rt for 5 h. The solution was evaporated and the residuechromatographed on silica column using CH₂Cl₂/methanol (9:1) as eluentto yield t-butyloxy-carbonyl-3,3-dimethyl-dl-proline (200 mg) as an oil(LC/Mass, + ion): 244 (M+H).

The title compound in Example 67 was prepared by the peptide coupling ofthe t-butyloxycarbonyl-3,3-dimethyl-dl-proline amino acid described inStep 3 followed by dehydration and deprotection as described in generalmethod C. MS (M+H) 220.

EXAMPLE 68

Sodium ethoxide (940 mg of 21 wt % solution in ethanol, 2.9 mmol) inethanol (2 mL) was added to a stirred solution of diethylacetamidomalonate (4.31 g, 19,8 mmol) in EtOH (23 mL) at rt under argon.The reaction mixture was cooled to 0° C.; and trans-2-pentenal (1.51 g,18.0 mmol) was added dropwise maintaining the reaction temperature at<5° C. After the addition, the reaction was allowed to warm to rt,stirred for 4 h, then quenched with acetic acid (460 μl). The solutionwas concentrated in vacuo, and the residue dissolved in EtOAc (25 mL),washed with 10% NaHCO₃ solution (2×5 mL), brine and dried (MgSO₄). Thesolution was filtered and concentrated to a 10 mL volume, then heated toreflux and diluted with hexane (20 mL). Upon cooling to rt, the titlecompound precipitated and was collected to give 3.0 g (50%) of the Step1 compound (mp 106-109° C.; LC/Mass: + ions, 324 M+Na).

To a solution of Step 1 compound (2.87 g, 9.5 mmol) and triethylsilane(2.28 mL, 14.3 mmol) in CH₂Cl₂ (30 mL) under argon was added TFA (7.35mL, 95.3 mmol) dropwise with stirring while maintaining the internaltemperature at 25° C. by means of an ice bath. After stirring for 4 h atrt, the solution was concentrated. The residue was diluted with CH₂Cl₂(100 mL) , then treated with H₂O (50 mL) and solid Na₂CO₃ with vigorousstirring until the mixture was basic. The organic layer was separated,dried (Na₂SO₄), filtered, then concentrated to give the Step 2 compoundas a yellow oil which was used without further purification (LC/Mass: +ions, 308 M+Na).

Step 2 compound (3.73 g, 9.5 mmol) was suspended in 6 N HCl (20 mL) andHOAc (5 mL) and heated at reflux for 20 h. The reaction mixture was thencooled, washed with EtOAc (20 mL), then concentrated to give an oilwhich crystallized upon trituration with ether to give the titlecompound (1.2 g, 70.6%) (LC/Mass, + ion): 144 (M+H).

Step 3 compound (692 mg, 3.76 mmol) was dissolved in acetone (12 mL)/water (12 mL). To this clear solution was added triethylamine (1.9 mL,12.8 mmol) and di-t-butyl dicarbonate (928 mg, 4.24 mmol). The reactionmixture was stirred at rt for 18 h. The solvents were evaporated and theresidue chromatographed on silica with 1:9 methanol:CH₂Cl₂ to give theStep 4 compound as an oil (LC/Mass: + ions, 266 M+Na).

Example 68 compound was prepared by peptide coupling of Step 4 aminoacid followed by dehydration and deprotection as described in generalmethod C (MS (M+H) 234).

EXAMPLE 69

Sodium ethoxide (940 mg, 2.9 mmol; 21% w/w solution in ethanol) inethanol (2 mL) was added to a stirred solution of diethylacetamidomalonate (4.31 g, 19.8 mmol) in EtOH (23 mL) at rt under argon.The reaction mixture was cooled to 0° C.; and 4-methyl-2-pentenal (1.77g, 18.0 mmol)was added dropwise maintaining the reaction temperature at<5° C. After the addition, the reaction was allowed to warm to rt,stirred for 4 h, then quenched with acetic acid (460 μl). The solutionwas concentrated and the remainder dissolved in EtOAc (25 mL). Theorganics were washed with 10% NaHCO₃ solution (2×5 mL), brine and dried(MgSO₄). The solution was filtered and concentrated to 10 mL volume,then heated to reflux and treated with hexane (20 mL). On cooling, theStep 1 compound precipitated and was collected (3.3 g) (LC/Mass, + ion):338 (M+Na).

To a solution of Step 1 compound (3.0g, 9.5 mmol) and triethylsilane(2.28 mL, 14.3 mmol) in CH₂Cl₂ (30 mL) under argon was added TFA (7.35mL, 95.3 mmol) dropwise with stirring while maintaining the internaltemperature at 25° C., by means of an ice bath. After stirring for 4 hat rt, the solution was concentrated, the residue diluted with CH₂Cl₂(100 mL), then treated with H₂O (50 mL) and solid Na₂CO₃ with vigorousstirring until the mixture was basic. The organic layer was separated,dried (Na₂SO₄), filtered, then concentrated to give the title compoundas an oil which was used without further purification (LC/Mass:+ ions,300 M+H).

Step 2 compound (3.8 g, 9.5 mmol) was suspended in 6 N HCl (20 mL) andHOAc (5 mL) and heated at reflux for 20 h. The reaction mixture wascooled, washed with EtOAc (20 mL), then concentrated to give an oilwhich crystallized upon trituration with ether to give the step 3compound (1.4 g, 76.0%). LC/Mass: + ions, 158 (M+H).

Step 3 compound (728 mg, 3.76 mmol) was dissolved in a 1:1 acetone/watersolution (24 mL). To this clear solution was added triethylamine (1.9mL, 12.8 mmol) and di-t-butyl dicarbonate (928 mg, 4.24 mmol). Thereaction mixture was stirred at rt for 18 h. The solution was evaporatedand the residue chromatographed on silica column using CH₂Cl₂/methanol(9:1) as eluent to give the title compound as an oil (LC/Mass, + ion):258 (M+H).

Example 69 compound was prepared by peptide coupling of Step 4 aminoacid followed by dehydration and deprotection as described in generalmethod C (MS (M+H) 248).

EXAMPLE 70

Step 1 compound was prepared by the procedure described in GeneralMethod C starting from N-Boc-S-t-butylcysteine.

A 25-mL round-bottomed flask equipped with a magnetic stirring bar andN₂ inlet was charged with Step 1 compound (78 mg, 0.21 mmol) andchloroform (3 mL). The mixture was cooled to 0° C. and treated withm-chloroperoxybenzoic acid (85 mg, 0.44 mmol) in CHCl₃ (2 mL). After 3 hthe solution was diluted with CHCl₃ (7 mL), washed with 5% NaHCO₃ (2×5mL), H₂O and dried over Na₂SO₄. Removal of solvent gave crude sulfoxide(100 mg), which was used without further purification (LC/Mass, + ions):384 (M+H).

Trifluoroacetic acid (1.5 mL) was added to a cooled (0° C.) solution ofStep 2 compound (100 mg, 0.26 mmol) in 5 mL CH₂Cl₂. The solution wasthen stirred at 0° C. for 1.5 h, diluted with CH₂Cl₂ (5 mL) andconcentrated under reduced pressure to a thick oil. The product waspurified by reverse phase preparative column chromatography on a YMC S5ODS 20×100 mm column to give the title compound of Example 70 , 17 mg,16%. Purification conditions: gradient elution from 10%methanol/water/0.1 TFA to 90% methanol/water/0.1 TFA over 15 min 5 minhold at 90% methanol/water/0.1 TFA. Flow rate: 20 mL/min. Detectionwavelength: 220. Retention Time 10 Min (LC/Mass, + ion): 284 (M+H).

EXAMPLE 71

A 25-mL round-bottomed flask equipped with a magnetic stirring bar andN₂ inlet was charged with compound from Example 70, Step 1 (78 mg, 0.21mmol) in chloroform (3 mL). The mixture was cooled to 0° C. and treatedwith m-chloroperoxybenzoic acid (144 mg, 0.84 mmol) in CHCl₃ (2 mL).After 30 min at rt, the solution was diluted with CHCl₃ (7 mL), washedwith 5% NaHCO₃ (2×10 mL), H₂O and dried over Na₂SO₄. Removal of solventgave the crude sulfone (100 mg), which was used without furtherpurification (LC/Mass, + ion): 344 (M+H−Bu).

Trifluoroacetic acid (1.5 mL) was added to a cooled (0° C.) and stirredsolution of Step 1 compound (100 mg, 0.26 mmol) in 5 mL CH₂Cl₂. Thesolution was stirred at 0° C. for 30 min, diluted with CH₂Cl₂ (5 mL) andconcentrated under reduced pressure to a thick oil. The product waspurified by reverse phase preparative column chromatography on a YMC S5ODS 20×100 mm column to give the title compound, 14 mg, 17%.Purification conditions: gradient elution from 10% methanol/water/0.1TFA to 90% methanol/water/0.1 TFA over 15 min 5 min hold at 90%methanol/water/0.1 TFA. Flow rate: 20 mL/min. Detection wavelength: 220.Retention Time 10 Min. (LC/Mass, + ion): 300 (M+H).

EXAMPLE 72

The title compound was prepared following a published procedure (Sasakiet al, Tetrahedron Lett. 1995, 36, 3149, Sasaki et al. Tetrahedron 1994,50, 7093) used to synthesize (2S,3R,4S)-N-Boc-3,4-methano-L-prolinecarboxylate. The corresponding amide was prepared by general method Aand deprotected with TFA to give the TFA salt also as described ingeneral method A.

EXAMPLE 73

The title compound was prepared by coupling(2S,3R,4S)-3,4-methano-L-proline carboxamide-N-trifluoroacetatedescribed in Example 72 with L-cyclohexylglycine and then dehydrated tothe amide with POCl₃/imidazole and deprotected (N-terminal nitrogen)with TFA using general C (FAB MH+248).

EXAMPLE 74

The title compound was prepared by coupling(2S,3R,4S)-3,4-methano-L-proline carboxamide-N-trifluoroacetatedescribed in Example 72 with L-tert-butylglycine and then dehydrated tothe amide with POCl₃/imidazole and deprotected (N-terminal nitrogen)with TFA using general C (FAB MH+222).

EXAMPLE 75

The title compound was prepared by coupling(2S,3R,4S)-3,4-methano-L-proline carboxamide-N-trifluoroacetatedescribed in Example 72 with L-valine and then dehydrated to the amidewith POCl₃/imidazole and deprotected (N-terminal nitrogen) with TFAusing general C (FAB MH+207).

EXAMPLE 76

The title compound was prepared by coupling(2S,3R,4S)-3,4-methano-L-proline carboxamide-N-trifluoroacetatedescribed in Example 72 withN-(tert-butyloxycarbonyl)-(1′ethylcyclopentyl)glycine described inGeneral Method B and then dehydrated to the amide with POCl₃/imidazoleand deprotected (N-terminal nitrogen) with TFA using general C (FABMH+262).

EXAMPLE 77

The title compound was prepared by coupling(2S,3R,4S)-3,4-methano-L-proline carboxamide-N-trifluoroacetatedescribed in Example 72 withN-(tert-butyloxycarbonyl)-(1′vinylcyclopentyl)glycine described inGeneral Method B and then dehydrated to the amide with POCl₃/imidazoleand deprotected (N-terminal nitrogen) with TFA using General Method C(FAB MH+260).

EXAMPLE 78

N-[((S)-cyclopentylvinyl)-N-tert-butoxycarbonylglycinyl]-(2S,4S,5S)-2-cyano-4,5-methano-L-prolylamide(70 mg, 0.19 mmol) described in General Method C, Step 2 was dissolvedin a mixture of 2 mL t-BuOH/3 mL THF and N-methylmorpholine-N-oxide(33mg, 0.28 mmol) was added followed by osmium tetroxide (0.1 mmol, 50mol %). The reaction was quenched with 1 mL of 10% aqueous Na₂SO₃ andwas taken up in EtOAc and washed with H₂O 5 mL, dried (Na₂SO₄),filtered, evaporated and purified by silica gel flash chromatography (5%MeOH/CH₂Cl₂) to give 41 mg (55%) of the protected diol as an oil. Thetitle compound was obtained by deprotection of the amine functionalitywith TFA according to General Method C (FAB MH+294).

EXAMPLE 79

General Procedure I: Synthesis of Quaternary Amino Acids Via MichaelAddition to Malonates followed by Selective Hydrolysis and CurtiusRearrangement. Examples 79-84.

Cyclohexanone and diethylmalonate underwent Knoevenagel condensationmediated by titanium tetrachloride in THF and CCl₄ to give 40. Copper(I) mediated Grignard addition of methylmagnesium bromide gave 41 whichwas selectively saponified to 42. Curtius rearrangement with trapping bybenzyl alcohol gave 43 which was converted to 44 by a standarddeprotection-protection protocol. Ester 44 was saponified to give thequaternary amino acid 45.

According to literature procedure (Tetrahedron 1973, 29, 435), a mixtureof dry tetrahydrofuran (400 mL) and dry carbon tetrachloride (50 mL) wascooled to 0° C. (ice-salt bath) and treated with titanium tetrachloride(22.0 mL, 0.2 mole). The resulting yellow suspension was stirred at 0°C. for 5 min, treated sequentially with cyclohexanone (10.3 mL, 0.1mole) and distilled diethylmalonate (15.2 mL, 0.1 mole) then stirred at0° C. for 30 min. The reaction mixture was then treated with a solutionof dry pyridine (32 mL, 0.40 mole) in dry THF (60 mL), stirred at 0° C.for 1.0 h, then at rt for 72 h. The reaction mixture was quenched withwater (100 mL), stirred for 5 min then extracted with ether (2×200 mL).The combined organic extracts were washed with saturated sodium chloride(100 mL), saturated sodium bicarbonate (100 mL) and brine (100 mL),dried over anhydrous magnesium sulfate, filtered and concentrated. Flashchromatography using 5% EtOAc in hexane gave step 1 compound as a lightyellow oil. Yield: 5.25 g (22%). MS (M+Na) 263.

According to literature (Org. Syn. VI, 442, 1988; Liebigs Ann. Chem.1981, 748) a mixture of 3.0 M methylmagnesium iodide (3.1 mL, 9.36 mmol)and cuprous chloride (9.0 mg) was stirred at 0° C. (ice-salt waterbath), treated with a solution of Step 1 compound (1.5 g, 6.24 mmol) indry ether (1.8 mL) over 5 min and stirred at 0° C. for 1 h, then at rtfor 40 min. The mixture was slowly added to a slurry of ice and water(15 mL), treated dropwise with 10% HCl (3.7 mL) then extracted withEtOAc (3×25 mL). The combined organic extracts were washed with 1%sodium thiosulfate (2.0 mL) and saturated sodium chloride (2.0 mL),dried over anhydrous magnesium sulfate, filtered, and concentrated.Flash chromatography on a silica gel column using 5% ether in hexane(1.0 L) gave step 2 compound as a clear syrup. Yield: 1.09 g,(68%). MS(M+H)257.

A solution of Step 2 compound (1.09 g, 4.03 mmol) in a mixture ofmethanol (5.4 mL) and water (2.7 mL) was treated with 1N sodiumhydroxide (4.84 mL, 4.84 mmol or 1.2 equiv) and stirred at rt for 6days. The reaction mixture still showed the presence of startingmaterial, so THF (4.0 mL) was added and the entire mixture stirred foranother 2 days. The solution was evaporated to dryness and the resultingsyrup partitioned between water (8.0 mL) and ether (15 mL). The aqueousphase was acidified with 1N hydrochloric acid (4.8 mL) to pH 2-3 andextracted with EtOAc (3 ×25 mL). The combined organic extracts werewashed with brine (10.0 mL), dried over anhydrous magnesium sulfate,filtered, and concentrated to give step 3 compound as a thick syrup.Yield: 875 mg, (95.1%). MS (M+H) 229.

Or alternately: solutions of the diester in a mixture of ethanol, THF,dioxane and water or mixtures thereof may be hydrolyzed with sodiumhydroxide.

According to literature (J. Org. Chem 1994, 59, 8215), a solution ofStep 3 compound (0.875 g, 3.83 mmol) in dry benzene (4.0 mL) was treatedwith triethylamine (0.52 mL, 3.83 mmol) and diphenylphosphoryl azide(0.85 mL, 3.83 mmol), refluxed under nitrogen for 1 h and cooled to rt.The solution was treated with benzyl alcohol (0.60 mL, 5.75 mmol or 1.5equiv), refluxed for 17 h, cooled then diluted with ether (40 mL). Thesolution was washed with 10% aqueous citric acid (2×3 mL),back-extracting the citric acid wash with ether (40 mL). The combinedorganic extracts were washed with 5% sodium bicarbonate (2×3 mL), dried(MgSO₄), filtered, and concentrated. Flash chromatography on silica gelof the crude product with 10% EtOAc in hexane (1.0 L) gave step 4compound as a clear thick syrup. Yield: 1.15 g (90%). MS(M+H) 334.

A solution of Step 4 compound (1.15 g, 3.46 mmol) in EtOAc (60 mL) wastreated with palladium hydroxide on carbon (298 mg) and hydrogenated atrt for 20 h. The mixture was filtered through a celite pad and thenwashing the pad well with EtOAc (3×25 mL) then the filtrate wasconcentrated to give the free amine. A solution of the amine intetrahydrofuran (12 mL) and water (12 mL) was treated with di-t-butyldicarbonate (1.0 g, 4.58 mmol or 1.48 equiv) and potassium carbonate(854 mg, 6.18 mmol or 2.0 equiv), then stirred at rt for 20 h. Thereaction mixture was partitioned between water (8 mL) and diethyl ether(3×40 mL) and the combined organic extracts were washed with brine (8mL), dried (MgSO₄), filtered, and concentrated. Flash chromatography ofthe crude product with 10% EtOAc in hexane (1 L) gave step 5 compound asa clear thick syrup. Yield: 1.18 g (100%). MS:(M+H) 300.

Other methods can also be employed, for example:

According to Tetrahedron Lett. 1988, 29, 2983, where a solution of thebenzylcarbamate in ethanol may be treated with triethylsilane (2 equiv),di-t-butyldicarbonate (1.1 equiv), catalytic palladium acetate andtriethylamine (0.3 equiv) to give the BOC-protected amine in a “one-pot”manner.

Or alternately: Solutions of the benzylcarbamate in methanol may besubjected to hydrogenolysis in the present of di-t-butyldicarbonate togive the BOC-protected amine in a “one-pot” manner.

A solution of Step 5 compound (1.18 g, 3.09 mmol) in dioxane (8.0 mL)was treated with 1N sodium hydroxide (9.1 mL, 9.1 mmol or 3.0 equiv) andstirred at 60° C. (oil bath) for 28 h. The reaction mixture wasconcentrated to a syrup which was dissolved in water (15 mL) andextracted with ether (25 mL). The aqueous phase was acidified to pH 2-3with 1N hydrochloric acid (9.2 mL) then extracted with EtOAc (3×50 mL).The combined organic extracts were washed with saturated sodium chloride(10 mL), dried (MgSO₄), filtered, and concentrated to give Step 6compound as an off-white solid. Yield: 808 mg (96%). MS (M+H) 272.

The title compound was prepared from Step 6 compound according to theprocedure in General Method C where the amino acid was coupled, theamide was dehydrated, and the protecting group removed to give the titlecompound. MS (M+H) 262.

Compounds 90-100 were prepared by General Method I and General Method Cstarting from cyclohexanone, cyclopentanone and cyclobutanone, andemploying methyl-, ethyl-, allyl- and propylmagnesium halides asGrignard reagents.

TABLE 5

MS Data Example # Cycloalkane R M + H 79 cyclohexane Methyl 262 80cyclohexane Ethyl 276 81 cyclopentane Methyl 248 82 cyclopentane Allyl274 83 cyclopentane Propyl 276 84 cyclobutane Methyl 234

EXAMPLE 85

According to Example 79: A mixture of dry carbon tetrachloride (50 mL)was cooled to 0° C. (ice-salt bath) and treated with titaniumtetrachloride (11.0 mL, 0.1 mol). The resulting yellow suspension wasstirred at 0° C. for 5 min, treated sequentially with cyclopentanone(4.42 mL, 0.05 mol) and distilled diethylmalonate (7.6 mL, 0.05 mol)then stirred at 0° C. for 30 min The reaction mixture was then treatedwith a solution of dry pyridine (16 mL, 0.20 mol) in dry THF (30 mL),stirred at 0° C. for 1.0 h, then at rt for 20 h. The reaction mixturewas quenched with water (50 mL), stirred for 5 min then extracted withether (2×100 mL). The combined organic extracts were washed withsaturated sodium chloride (50 mL), saturated sodium bicarbonate (50 mL)and brine (50 mL), dried (MgSO₄), filtered and concentrated. Flashchromatography using 5% EtOAc in hexane gave Step 1 compound as a lightyellow oil. Yield: 7.67 g (68%). MS (M+H) 226.

A solution of Step 1 compound (1.00 g 4.42 mmol) in methanol (50 mL) wastreated with 10% Pd/C (0.20 g, 10 mol %) and hydrogenated (balloonpressure) at rt for 20 h. The mixture was diluted with methanol andfiltered through a pad of celite. The filtrate was concentrated andpurified by flash column chromatography on silica gel with 7% EtOAc inhexanes to give 0.84 g (91%) of Step 2 compound. MS (M+H) 229.

The Step 3 compound was prepared by the process outlined in GeneralMethod H, where the ester underwent hydrolysis, Curtius Rearrangement,protecting group exchange, and again final ester hydrolysis.

The title compound was prepared from Step 3 compound according to theprocedure in General Method C where the amino acid was coupled, theamide was dehydrated, and the protecting group removed to give the titlecompound. MS (M+H) 234.

Examples 86 and 87 were prepared by the procedures used for Example 85starting from cyclohexanone and cyclobutanone respectively

Mass Spec Example # Cycloalkane M + H 85 cyclopentyl 234 86 cyclohexyl248 87 cyclobutyl 220

EXAMPLE 89

Step 1 compound was prepared in Example 6 Step 1.

The title compound was prepared from Step 1 compound according toGeneral Method C, where the carboxylic acid underwent a peptidecoupling, the amide dehydration and protecting group removal. MS (M+H)218.

EXAMPLES 90 TO 99

Examples of compounds where X=H include the following compounds whichmay be prepared employing procedures as described hereinbefore.

Ex. # n x y R¹ R² R³ R⁴ 90 0 0 1 t-Bu H H — 91 0 0 1 adamantyl H H — 920 0 1

H H — 93 0 0 1

H Me — 94 0 1 0 t-Bu H H — 95 0 1 0 adamantyl H H — 96 0 1 0

H H — 97 0 1 0

H Me — 98 1 0 1 H H H t-Bu 99 1 1 0 Me H H t-Bu

EXAMPLES 100 TO 109

Examples of compounds where n=1 include the following compounds whichmay be prepared employing procedures as described hereinbefore.

Ex. # X x y R¹ R² R³ R⁴ 100 CN 0 1 H H H t-Bu 101 CN 0 1 H H H adamantyl102 CN 0 1 H Me H

103 CN 0 1

H Me H 104 CN 1 0 t-Bu H H H 105 CN 1 0 adamantyl H H Me 106 CN 1 0

Et H H 107 CN 1 0 H H Me

108 H 0 1 t-Bu H H H 109 H 1 0 Me H H t-Bu

What is claimed is:
 1. A compound having the structure

wherein x is 0 or 1 and y is 0 or 1, provided that x=1 when y=0 and x=0when y=1; and wherein n is 0 or 1; X is H or CN; R¹, R², R³ and R⁴ arethe same or different and are independently selected from hydrogen,alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl, bicycloalkyl,tricycloalkyl, alkylcycloalkyl, hydroxyalkyl, hydroxyalkylcycloalkyl,hydroxycycloalkyl, hydroxybicycloalkyl, hydroxytricycloalkyl,bicycloalkylalkyl, alkylthioalkyl, arylalkylthioalkyl, cycloalkenyl,aryl, aralkyl, heteroaryl, heteroarylalkyl, cycloheteroalkyl orcycloheteroalkylalkyl; all optionally substituted through availablecarbon atoms with 1, 2, 3, 4 or 5 groups selected from hydrogen, halo,alkyl, polyhaloalkyl, alkoxy, haloalkoxy, polyhaloalkoxy,alkoxycarbonyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl,polycycloalkyl, heteroarylamino, arylamino, cycloheteroalkyl,cycloheteroalkylalkyl, hydroxy, hydroxyalkyl, nitro, cyano, amino,substituted amino, alkylamino, dialkylamino, thiol, alkylthio,alkylcarbonyl, acyl, alkoxycarbonyl, aminocarbonyl,alkynylaminocarbonyl, alkylaminocarbonyl, alkenylaminocarbonyl,alkylcarbonyloxy, alkylcarbonylamino, arylcarbonylamino,alkylsulfonylamino, alkylaminocarbonylamino, alkoxycarbonylamino,alkylsulfonyl, aminosulfinyl, aminosulfonyl, alkylsulfinyl, sulfonamidoor sulfonyl; and R¹ and R³ may optionally be taken together to form—(CR⁵R⁶)_(m)— where m is 2 to 6, and R⁵ and R⁶ are the same or differentand are independently selected from hydroxy, alkoxy, H, alkyl, alkenyl,alkynyl, cycloalkyl, halo, amino, substituted amino, cycloalkylalkyl,cycloalkenyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl,cycloheteroalkyl, cycloheteroalkylalkyl, alkylcarbonylamino,arylcarbonylamino, alkoxycarbonylamino, aryloxycarbonylamino,alkoxycarbonyl, aryloxycarbonyl, or alkylaminocarbonylamino, or R¹ andR4 may optionally be taken together to form —(CR⁷R⁸)_(p)— wherein p is 2to 6, and R⁷ and R⁸ are the same or different and are independentlyselected from hydroxy, alkoxy, cyano, H, alkyl, alkenyl, alkynyl,cycloalkyl, cycloalkylalkyl, cycloalkenyl, halo, amino, substitutedamino, aryl, arylalkyl, heteroaryl, heteroarylalkyl, cycloheteroalkyl,cycloheteroalkylalkyl, alkylcarbonylamino, arylcarbonylamino,alkoxycarbonylamino, aryloxycarbonylamino, alkoxycarbonyl,aryloxycarbonyl, or alkylaminocarbonylamino, or optionally R¹ and R³together with

 form a 5 to 7 membered ring containing a total of 2 to 4 heteroatomsselected from N, O, S, SO, or SO₂; or optionally R¹ and R³ together with

 form a 4 to 8 membered cycloheteroalkyl ring wherein thecycloheteroalkyl ring has an optional aryl ring fused thereto or anoptional 3 to 7 membered cycloalkyl ring fused thereto; with the provisothat where x is 1 and y is 0, X is H, n is o, and one of R¹ and R² is Hand the other is alkyl, then R³ is other than pyridyl or substitutedpyridyl; including all stereoisomers thereof; andor a pharmaceuticallyacceptable salt thereof, or a prodrug ester thereof, and allstereoisomers thereof.
 2. The compound as defined in claim 1 having thestructure:


3. The compound as defined in claim 1 having the structure:


4. The compound as defined in claim 1 having the structure:


5. The compound as defined in claim 1 having the structure:


6. The compound as defined in claim 1 wherein: R³ is H, R¹ is H, alkyl,cycloalkyl, bicycloalkyl, tricycloalkyl, alkylcycloalkyl, hydroxyalkyl,hydroxyalkylcycloalkyl, hydroxycycloalkyl hydroxybicycloalkyl, orhydroxytricycloalkyl, R² is H or alkyl, n is 0, X is CN.
 7. The compoundas defined in claim 1 wherein the cyclopropyl fused to the pyrrolidinehas the configuration:


8. A compound having the structure:

or a pharmaceutically acceptable salt thereof.
 9. The compound asdefined in claim 8 wherein the pharmaceutically acceptable salt is thehydrochloride salt or the trifluoroacetic acid salt.
 10. A compoundwhich is

wherein R¹ is alkyl, cycloalkyl, bicycloalkyl, tricycloalkyl,alkylcycloalkyl, hydroxyalkyl, hydroxycycloalkyl,hydroxyalkylcycloalkyl, hydroxybicycloalkyl, or hydroxytricycloalkyl, or

wherein R¹ is alkyl, cycloalkyl, bicycloalkyl, tricycloalkyl,alkylcycloalkyl, hydroxyalkyl, hydroxycycloalkyl,hydroxyalkylcycloalkyl, hydroxybicycloalkyl, or hydroxytricycloalkyl.11. A pharmaceutical composition comprising a compound as defined inclaim 1 and a pharmaceutically acceptable carrier therefor.
 12. Apharmaceutical combination comprising a DP4 inhibitor compound asdefined in claim 1 and an antidiabetic agent other than a DP4 inhibitorfor treating diabetes and related diseases, an anti-obesity agent and/ora lipid-modulating agent.
 13. The pharmaceutical combination as definedin claim 12 comprising said DP4 inhibitor compound as defined in claim 1and an the antidiabetic agent other than a DP4 inhibitor.
 14. Thecombination as defined in claim 13 wherein the antidiabetic agent is 1,2, 3 or more of a biguanide, a sulfonyl urea, a glucosidase inhibitor, aPPAR γ agonist, a PPAR α/γ dual agonist, an SGLT2 inhibitor, an aP2inhibitor, a glycogen phosphorylase inhibitor, an AGE inhibitor, aninsulin sensitizer, a glucagon-like peptide-1 (GLP-1) or mimeticthereof, insulin and/or a meglitinide.
 15. The combination as defined inclaim 14 wherein the antidiabetic agent is 1, 2, 3 or more of metformin,glyburide, glimepiride, glipyride, glipizide, chlorpropamide,gliclazide, acarbose, miglitol, pioglitazone, troglitazone,rosiglitazone, insulin, G1 -262570, isaglitazone, JTT-501, NN-2344,L895645, YM-440, R-119702, AJ9677, repaglinide, nateglinide, KAD1129,AR-HO39242, GW-409544, KRP297, AC2993, Exendin-4, LY307161, NN2211,and/or LY315902.
 16. The combination as defined in claim 13 wherein thecompound as defined in claim 1 is present in a weight ratio to theantidiabetic agent within the range from about 0.01 to about 100:1. 17.The combination as defined in claim 12 wherein the anti-obesity agent isa beta 3 adrenergic agonist, a lipase inhibitor, a serotonin (anddopamine) reuptake inhibitor, a thyroid receptor beta compound, ananorectic agent, and/or a fatty acid oxidation upregulator.
 18. Thecombination as defined in claim 17 wherein the anti-obesity agent isorlistat, ATL-962, AJ9677, L750355, CP331648, sibutramine, topiramate,axokine, dexamphetamine, phentermine, phenylpropanolamine, famoxin,and/or mazindol.
 19. The combination as defined in claim 12 wherein thelipid modulating agent is an MTP inhibitor, an HMG CoA reductaseinhibitor, a squalene synthetase inhibitor, a fibric acid derivative, anupregulator of LDL receptor activity, a lipoxygenase inhibitor, an ACATinhibitor, a cholesteryl ester transfer protein inhibitor, or an ATPcitrate lyase inhibitor.
 20. The combination as defined in claim 19wherein the lipid modulating agent is pravastatin, lovastatin,simvastatin, atorvastatin, cerivastatin, fluvastatin, nisvastatin,visastatin, fenofibrate, gemfibrozil, clofibrate, implitapide, CP-529,414, avasimibe, TS-962, MD-700, and/or LY295427.
 21. The combination asdefined in claim 19 wherein the DP4 inhibitor compound as defined inclaim 1 is present in a weight ratio to the lipid-modulating agentwithin the range from about 0.01 to about 100:1.
 22. A pharmaceuticalcombination comprising a DP4 inhibitor compound as defined in claim 1and an agent for treating infertility, an agent for treating polycysticovary syndrome, an agent for treating a growth disorder and/or frailty,an anti-arthritis agent, an agent for preventing or inhibiting allograftrejection in transplantation, an agent for treating autoimmune disease,an anti-AIDS agent, an agent for treating inflammatory boweldisease/syndrome, an agent for treating anorexia nervosa, ananti-osteoporosis agent and/or an anti-obesity agent.
 23. A method fortreating diabetes, insulin resistance, hyperglycemia, hyperisulinemia,or elevated blood levels of free fatty acids or glycerol, obesity,Syndrome X, dysmetabolic syndrome, diabetic complications,hypertriglyceridemia, hyperinsulinemia, atherosclerosis, impairedglucose homeostasis, impaired glucose tolerance, infertility, polycysticovary syndrome, growth disorders, frailty, arthritis, allograftrejection in transplantation, autoimmune diseases, AIDS, intestinaldiseases, inflammatory bowel syndrome, nervosa, osteoporosis, or animmunomodulatory disease or a chronic inflammatory bowel disease, whichcomprises administering to a mammalian species in need of treatment atherapeutically effective amount of a compound as defined in claim 1.24. The method as defined in claim 23 for treating type II diabetesand/or obesity.
 25. A compound that is

or a pharmaceutically acceptable salt thereof.
 26. The compound asdefined in claim 25, wherein the pharmaceutically acceptable salt is thehydrochloride salt.
 27. A pharmaceutical composition comprising thecompound of claim 25 and a pharmaceutically acceptable carrier therefor.28. A pharmaceutical composition comprising the compound of claim 26 anda pharmaceutically acceptable carrier therefor.
 29. The composition ofclaim 27 or 28 further comprising an antidiabetic agent other than a DP4inhibitor.
 30. The composition of claim 29 wherein the antidiabeticagent is metformin.
 31. The composition of claim 29, wherein theantidiabetic agent is a SGLT2 inhibitor.
 32. A method for treatingdiabetes, insulin resistance, hyperglycemia, hyperinsulinemia, impairedglucose homeostasis, or impaired glucose tolerance in a mammalcomprising administering to the mammal a pharmaceutical compositioncomprising a compound that is

or a pharmaceutically acceptable salt thereof, and a pharmaceuticallyacceptable carrier therefor.
 33. The method of claim 32, wherein thepharmaceutically acceptable salt is the hydrochloride salt.
 34. Themethod of claim 32, for treating diabetes.
 35. The method of claim 33,for treating diabetes.
 36. The method of any one of claim 32, 33, 34, or35 wherein the pharmaceutical composition further comprises anantidiabetic agent other than a DP4 inhibitor.
 37. The method of claim36, wherein the antidiabetic agent is metformin.
 38. The method of claim36, wherein the antidiabetic agent is a SGLT2 inhibitor.
 39. A methodfor treating type II diabetes in a mammal comprising administering tothe mammal a pharmaceutical composition comprising a compound that is

or a pharmaceutically acceptable salt thereof, and a pharmaceuticallyacceptable carrier therefor.
 40. The method of claim 39, wherein thepharmaceutically acceptable salt is the hydrochloride salt.
 41. Themethod of any one of claims 39 or 40, wherein the pharmaceuticalcomposition further comprises an antidiabetic agent other than a DP4inhibitor.
 42. The method of claim 41, wherein the antidiabetic agent ismetformin.
 43. The method of claim 41, wherein the antidiabetic agent isa SGLT2 inhibitor.